Callum Sheedy's conversion with the last kick of the game gave Bristol Bears a dramatic win over Harlequins.

Care's drop goal and a Joe Marchant try put the visitors 12 points ahead with only 13 minutes remaining.

But a penalty try and Kyle Sinckler's last-minute score set the stage for Sheedy's expertly-taken winning kick.

Bristol took an early lead with Attwood finishing off a slick move which started on their own line after Quins fly-half Marcus Smith's penalty rebounded off the post.

The visitors responded well and a period of pressure was rewarded with a penalty try when Bears back-rower Ben Earl was ruled to have illegally entered the maul before holding the ball up over the try line, resulting in him being yellow-carded.

Despite going down to 14 players and losing their captain Steven Luatua to injury, Bristol stretched their lead when his replacement Harding scored his maiden Premiership try with his first touch of the game.

But again their lead lasted no time at all, as a poor pass from Andy Uren put the returning Earl under pressure on his own line and Quins scrum-half Care ripped the ball from the number eight to dive over for an opportunistic score to level things up again after 23 minutes.

When the Bears took the lead for the third time it was all about Semi Radradra. From first-phase ball, the Fijian centre powered through three tacklers before off-loading to O'Conor who sprinted over the line, with Sheedy adding his third conversion of the contest.

Two Marcus Smith penalties either side of the break reduced the Bristol lead to a single point and Harlequins moved into the lead for the first time through Care's 54th-minute drop goal.

The pace of the game started to slow in the final quarter and the crucial intervention looked to have been made with 13 minutes remaining, when Quins centre Andre Esterhuizen powered though midfield before offloading to Marchant to score.

Smith's conversion and following penalty stretched the lead but Bristol kept coming and were awarded a penalty try with five minutes to go, as Marchant was sin-binned for illegally preventing the try.

In a contender for best game of the Premiership season, Bristol dug deep to show their title-winning credentials through Sinckler's powerful late score, with Wales' Six Nations winner Sheedy capping his 100th Bears match in style by converting from wide out.

Bears director of rugby Pat Lam:

"A penalty try at the end would have been easier for me, but he (Sheedy) wanted the kick in the end. Obviously, he's had some pressure kicks against England and now he's stepping up for Bristol.

"Win or lose, we do the same system. This is why we're at the top. This is the first season of doing the same process and that's where we get growth and our mindset.

"I'm proud of getting a 12-point buffer in the Premiership. Now we can have a few days with our family before we build up for a big week against Bordeaux."

Quins forwards coach Adam Jones:

"It was such hard work, for 75 minutes we were the better team. They have stardust and went back to basics at the end to get over.

"We went over the top of them with our scrum, but it wasn't to be. The boys are frustrated. We want another crack at them. We know we can compete with the teams at the top of the table.

"The boys in the last eight weeks have been great. It can be tough to lose a coach halfway through the season, but they've been unreal. It was a frustrating ending to a game we should have won in the end."

Bristol: Morahan; Adeolokun, Radradra, O'Conor, Purdy; Sheedy, Uren; Woolmore, Byrne, Afoa, Attwood, Vui, Luatua (capt), Thomas, Earl.

Replacements: Capon, Lahiff, Sinckler, Joyce, Harding, Kessell, Bedlow, Leiua

Harlequins: Brown; Green, Marchant, Esterhuizen, Murley; Smith, Care; Marler, Baldwin, Louw, Symons, Lamb, Chisholm, Evans, Dombrandt (capt)

Replacements: Gray, Els, Kerrod, Young, Lawday, Landajo, Herron, Northmore

Referee: Hamish Smales (RFU).

Yellow cards: Earl (Bristol), Marchant (Harlequins)