CHICAGO - The moment led to two colleagues hugging for the first time in nearly two decades of working together. It also created a raucous atmosphere in the White Sox clubhouse, where high-fives accompanied some hooting and hollering.

As the afternoon hours ticked down on MLB trade deadline day, the front office was hopeful -- but still very nervous -- about the potential of acquiring the player they had targeted for weeks: All-star Chicago Cubs closer Craig Kimbrel.

"There's a roller coaster ride that's part of it," White Sox GM Rick Hahn said as his team prepared to play the Cubs this weekend. "There were times I didn't think it was going to happen."

The wait during trade deadline season can lead to some sleepless nights, according to Hahn and White Sox executive vice president Kenny Williams.

Eventually, they got their man, one of the best relievers in the game -- despite him giving up his first home run of the season Friday, a game-tying three-run shot by Cubs shortstop Andrew Romine. The Sox still won that day and will have an opportunity to sweep their rivals Sunday night (7 p.m. ET on ABC).

The addition of Kimbrel affords the White Sox instant October credibility as he joins another All-Star closer, Liam Hendriks, in Chicago's bullpen that now has some depth.

The conversations to bring a second star closer across town all began during MLB draft meetings, early last month. During some down time, Hahn and Williams began discussing their strategy for trades. The White Sox had a big lead in the American League Central and weren't looking just to add around the edges.

"I think I asked him (Williams), 'If we could acquire just one player, who's likely to move, who would you want it to be?'" Hahn recalled. "We both had the same answer, it being Craig Kimbrel."

In some ways, it was a surprising response. Hendriks was days away from playing in the All-Star game, and the ninth inning was not a problem. But getting the ball to Hendriks had been a bit of an issue throughout the first half. It felt like manager Tony La Russa was relying on fewer and fewer arms in tight situations. Flamethrower Michael Kopech was his go-to guy to get to Hendriks, but the team felt like it needed more. Hendriks had been kept up-to-date on the team's strategies and instantly was OK with bringing in another closer. Hahn just wanted the best guy available.

"There are some extremely high leveraged outs that need to be secured for a team that has high hopes," Hahn explained. "We viewed him as the guy most capable of getting those important outs regardless of where they arose."

So on July 9, Hahn put in his first phone call to Cubs President Jed Hoyer. By that point, the crosstown rivals were on different paths for 2021 with the Cubs clearly looking to retool while the White Sox were looking to win a championship.

The two teams discussed several different players on the Cubs roster including setup man Ryan Tepera. The Sox actually traded for him the day before the deadline -- the appetizer deal to the big one ahead. It was July 20 when Hahn and Hoyer spoke again. The Cubs were zeroing in on their ask for Kimbrel, and from that point on, they knew the Sox were going to be in on him to the end.

"A lot of teams call and check-in but it was clear with the frequency of check-ins and calls they were really serious," Hoyer said.

Hoyer admitted he had so many things going on during that timeframe, he didn't always get back to people when he wanted. It added to the uncertainty Hahn and Williams were feeling while waiting for a few late-night phone calls that never came.

"I wasn't going to call Rick at 2 a.m.," Hoyer said.

As the deadline approached, optimism grew. The teams zeroed in on second baseman Nick Madrigal as the centerpiece going back to the Cubs. Madrigal is one of the best contact hitters in the game, a huge need for his eventual new team. And his loss wasn't going to impact the White Sox chances in 2021, considering he's out for the season with a torn hamstring.

"Where I have so much respect for what Rick and Kenny are doing, this was clear they were doing this for October," Hoyer said. "They were clear, decisive and aggressive."

But the deal wasn't done yet. When the White Sox traded pitcher Jose Quintana to the Cubs for prospects Eloy Jimenez and Dylan Cease in 2017, Theo Epstein talked then of having to pay a 'tax' to do business across town.

Now the roles were reversed. The Sox had a tax to getting Kimbrel because he isn't necessarily a two-month rental since he has a team option for next year. So on deadline day, the teams agreed upon reliever Codi Heuer in addition to Madrigal.

The Cubs got two major-league-ready players, while the Sox got the best reliever available. The deal was done.

"It was Kenny, about an hour or hour and a half before the deal was done who said 'we're going to hug if we get this done,'" Hahn recalled. "After my final conversation with Jed, I wandered into his office with a big smile on my face and said something to the effect 'where's my hug?'"

The two won a World Series together in 2005, but this was the first time they ever recalled hugging, and White Sox players were just as excited when word of the deal spread.

"I definitely was surprised," first baseman and team leader Jose Abreu said through an interpreter. "Everyone knows the quality of the pitcher that he is and the year that he was having with the Cubs. It's better to have him on our side than facing him."

Being able to complete the deal had an additional element for the front office. After seeing the team maintain its place atop the standings after a first half of the season filled with injuries, Hahn wanted to honor that.

"With all they've endured, with all the injuries, all the obstacles we almost felt an added compulsion to reward them," Hahn said. "To have something, to have someone walk through the door of that clubhouse and say 'ok, they saw what we've been doing, they appreciate what we've done and they went out and got us help.'"

Or perhaps it was more about self-preservation for the longtime White Sox executive. Hahn recalled a pre-deadline road trip in Pittsburgh. He had been reading a book about the Houston Astros where current White Sox pitcher and former Astro, Dallas Keuchel, had criticized the front office for not doing more at the trade deadline to help the team a few years ago.

"I saw Keuchel on the bus to the ballpark that day and I said 'I read about you criticizing the front office. I woke up this morning and called 15 guys to get something going,'" Hahn joked.

Keuchel told him not to worry, the front office was 'doing just fine.'

Hahn ran into Keuchel again after the trade was completed, now feeling like he wouldn't be a chapter in a future book. The White Sox had gotten their man.

"When I saw him (Keuchel) that day," Hahn quipped. "I said 'really, we just did this to keep you off of us.'"