A last-gasp penalty try gave Harlequins a dramatic bonus-point victory over table toppers Exeter that breathed new life into their Gallagher Premiership season.

Joe Simmonds' one-man masterclass, including two tries, three penalties and three conversions, had looked like being enough for the Chiefs in a topsy-turvy encounter at the Stoop.

But Quins battered the line at the death as they chased a first league win in over a month and were rewarded with a late victory to move into sixth place.

They looked to have grabbed it when Gabriel Ibitoye went over. But referee Christophe Ridley had blown too early, and Quins were seemingly denied.

But the Chiefs, with first Ollie Devoto and then Alec Hepburn sent to the sin bin in a madcap finish, could not hold out forever and a final Quins scrum penalty was too much for Ridley to bear and he went under the posts to award Quins a penalty try and spark seismic celebrations.

Quins began the game with only one win in their last five league fixtures – including a humbling on home soil by London Irish earlier this month – and it showed in the early exchanges.

Danny Care failed to trap the kick off and then Phil Dollman, on the first proper Chiefs attack, brushed off Smith with ease to coast over down the left.

Smith began to make amends by slotting a penalty after the Quins scrum, anchored by Mark Lambert on his 250th appearance for the club, got the nudge on.

Joe Simmonds replied with a penalty of his own for a 10-3 lead for the league leaders. But Quins kept coming and when a clever Smith kick off turnover ball trapped Dollman in his in-goal area, Quins bludgeoned their way back into the contest.

After a succession of scrum penalties on the line, Care tapped and released the wrecking ball Paul Lasike to barge over, Smith converted and it was all square.

Smith and Joe Simmonds then traded penalties around the half-hour mark as the heavens opened and at the break the two sides went in locked at 13-13.

The sun was back out for the second half – and smiling on Quins it appeared – as brand-new replacement Tevita Cavubati wormed his way over.

But the Chiefs came roaring back. Sam Simmonds' searing break into the 22 leading two phases later to brother Joe drifting over down the left.

The youngster converted his own score and it was all square, but not for long. Elvis Taione went charging down the right, it was the younger Simmonds who again finished the job and added the extras for a 27-20 lead.

But Quins were not finished, emptying their bench and then levelling things up as man of the match Smith high-stepped his way over down the left and then added the tough extras into the wind.

But Joe Simmonds again had an answer, drilling his third penalty of the contest to make it 30-27 with quarter of an hour to go.

What then ensued was total one-way traffic as Quins chased the win.

Devoto saw yellow for a high shot on Smith and Quins earned penalty after penalty but were not settling for a draw. And after Hepburn also saw yellow their patience was eventually rewarded.