Bill Belichick brought a smart plan to Buffalo, even with two undrafted receivers as his top outside playmakers, and even with a third-quarter onside-kick call in his hip pocket that should have stayed there. The New England Patriots were driving toward a potential winning touchdown, toward Belichick's 36th victory in 41 games against the Bills as Patriots coach, before Cam Newton did something Tom Brady rarely did in the closing seconds of a game.

He found a way to lose it.

Did Brady jump out of his chair, or at least muffle a cheer, when Newton's fumble was recovered by Buffalo with 31 seconds left in a defeat that left the Patriots with their first 2-5 record since Brady was a fourth-string rookie in 2000? Maybe, maybe not. But asked the other day if he believes Brady finds satisfaction in the divergent paths of his Tampa Bay Buccaneers and Belichick's Patriots, Brady's friend and former Michigan teammate Aaron Shea, who played six seasons with the Cleveland Browns, responded, "Tom would never say that, but we all know who Tom Brady is. He's the ultimate competitor. ... I definitely think Tom has personal motivation when it comes to [Belichick], and I would too. If you got divorced, would you want your wife or husband to go with someone better?"

There is no rivalry in the NFL, or in American sports, quite like the rivalry between Brady and Belichick. Published league standings should include the eight divisions of the AFC and the NFC, and a ninth, unaffiliated division featuring two teams. Brady. Belichick. Entering Tampa Bay's Monday night game with the New York Giants, the quarterback has a commanding three-game lead over the head coach, who now owns his first four-game losing streak since 2002.

"It's the third time we've been in this situation this year, and unfortunately haven't been able to make enough plays to win," Belichick said after the Bills ended their seven-game New England losing streak. Later, he added, "I think we did a lot of things well enough to win, but not quite well enough to win, because we didn't win."

What else was there to say? The Patriots won six Super Bowls, 17 divisional titles (including the past 11), and countless down-to-the-wire games like these with Belichick and Brady on the same team. Now the 43-year-old Brady plays for the 5-2 Bucs, and the Patriots suddenly look like every other sorry AFC East opponent they've tormented for the better part of two decades. Even the Miami Dolphins are ahead of them, at 4-3, with an exciting young quarterback in Tua Tagovailoa and a coaching star-in-the-making in Brian Flores, raised in the Belichick way.

It's enough to convince millions of football fans that Brady has already answered the one question that had long hovered over the league: Who was more critical to the Patriots' success, the historically great quarterback or the historically great coach?

But just because Belichick has fallen behind Brady by a few touchdowns doesn't mean the game is over. He just discussed his team's big-picture problems with SiriusXM NFL Radio hosts Bill Lekas and Charlie Weis, his offensive coordinator for the first three Patriots titles -- a stunning move because Belichick almost never strays from the current week's challenges and opponent when making public comments. He might have felt the need to explain the losing while Brady was off winning for someone else.

Or, he might have wanted to remind football fans that it often takes a little time to create a winning team in a salary-cap sport. And that he once endured a brutal season in New England, just one, before he proved he could build a program unlike any the NFL has ever seen.

Truth is, Bill Belichick's 2020 team looks a bit like Bill Belichick's 2000 team. What do they have in common? Losing football. Identity-free football. Veteran quarterbacks who lost their only Super Bowl appearance a handful of seasons earlier, and who appear to be diminished versions of their former selves.

Drew Bledsoe ultimately got the big, long-term contract from the Patriots (thanks to owner Robert Kraft) that Newton, the more dynamic player, certainly didn't get (thanks to Belichick), but it seems likely that their New England endgames will land in the same smoky heap. Bledsoe lasted two starts on the $103 million deal he signed in March 2001, before his injury opened the door to Brady. Newton, who signed for one year and the minimum base salary of $1.05 million, might be one and done with Belichick whether or not Jarrett Stidham is deemed the long-term answer at the position.

But what happened in 2001, after Belichick lost 13 of his first 18 games as Patriots coach, should be a reminder of how quickly and dramatically things can change in the NFL. Before the start of 2020, Belichick didn't just lose Brady to free agency. He lost a league-high eight players to COVID-19 opt-outs, including two rock-solid pieces from the heart of his defense, Dont'a Hightower and Patrick Chung, who had made a combined 246 regular season and postseason starts for the Patriots. After dominating the AFC East and the league for so long, Belichick is now in the same position he was in 20 years ago: trying to start a brand-new program.

The opt-outs, injuries, the missed practice and game time to COVID-19, and the $26 million in dead salary-cap space assigned to a number of ex-Pats including Brady, Antonio Brown, and Stephen Gostkowski have compromised the transition from dynasty to whatever's next. "This is kind of the year that we've taken to, I would say, adjust our cap from the spending that we've had in accumulation of prior years," Belichick told SiriusXM NFL Radio. "We just haven't been able to have the kind of depth on our roster that we've had in some other years. That's provided more opportunity for younger players. So it's a combination of all the reasons."

Of course, no reason is more conspicuous in that combination than the living legend Belichick did not bring back. Brady's friend, Shea, offered the quarterback some advice before he signed with Tampa Bay. The two Michigan men are close. They lived one floor apart in college, in units directly above and below each other, and still talk regularly. Brady is the godfather of Shea's nine-year-old son, Kinzy, and now the franchise player for a head coach, Bruce Arians, who was Shea's offensive coordinator in Cleveland.

"I told Tom that BA is the smartest offensive guy I've ever been around," Shea said. "I told Tom, 'You're going to have so much fun with him.' I thought it was a match made in heaven.

"I look at how New England drafted wide receivers," he said. "No disrespect to anyone, but come on, man. Now look at the offense in Tampa. Tom brought (Rob Gronkowski) with him, and now he's got Antonio Brown. ... Now that Tom has his weapons, they're going to be a force to be reckoned with. I knew Tom had so much left in the tank and was so motivated. He's 43 and he's playing like he's 33."

Belichick, a youthful 68, is almost certain to coach into his 70s. Some believed he would outlast Brady, and give himself more chances to win another title; it is physically easier to coach than to play quarterback after all. But Brady is on record saying he might play beyond age 45, which seems more realistic by the week. Some years ago, after Shea told his friend that he had accomplished everything he could in the game and should consider retirement, Brady asked him if he liked his job. Shea was selling suites for the Browns, and he told the quarterback he was not enjoying it.

"There's nothing else I want to do except play quarterback in the NFL," Brady responded.

He has one more year left on his current deal.

"This will not be Tom's last contract," Shea said.

Meanwhile, Brady has a chance to lead the high-powered Bucs to their first postseason appearance in 13 years and to make Tampa Bay the first team to play a Super Bowl in its home stadium. Winning ring No. 7 in Raymond James Stadium with Arians as his coach, in the same year that Belichick potentially finishes under .500 for the first time since 2000, would be, in Shea's words, "a drop-the-mic moment for Tom."

No, Belichick should not have tried that surprise onside kick Sunday after New England tied the game in the third quarter; the Bills used the field position to ultimate score a touchdown on Josh Allen's run. "We're trying to make a positive play," Belichick said when asked about the strategy.

It wasn't easy to make positive plays without the injured Stephon Gilmore on defense, and without the injured Julian Edelman on offense. New England's top two wideouts were the undrafted Jakobi Meyers and Damiere Byrd, who combined for nine catches and 97 yards. Newton played a pretty good game, until the fatal fumble, but he hasn't been the same player -- and New England hasn't been the same team -- since he was sidelined by COVID-19. Newton has no touchdown passes against five interceptions in his past three starts.

Belichick said afterward that Newton is still his quarterback, but it's hard to see how much longer the Patriots can go without finding out what Stidham is all about. Funny how things work out. Chargers quarterback Justin Herbert told people before the draft that he thought New England would trade up in the first round to pick him; NBC Sports' Peter King had reported the Patriots were in love with Herbert as a prospect. Imagine what Belichick could have done with this transition year had he gotten his hands on him.

Hey, sometimes you get lucky in the draft, and find Tom Brady at pick No. 199, and sometimes you don't. This 2020 season is devolving into an excruciatingly painful exercise for Belichick, who has to live through some bad football while Brady is living happily ever after -- for now -- in Tampa.

But this game is not over. Bill Belichick can still find his long-term quarterback, and he can still build another championship team.

And Belichick can still hope that somebody else stops Tom Brady from winning another Super Bowl before he does.