Jack Carty showed nerves of steel to convert Naulia Dawai's injury-time try and steer Connacht to a terrific 20-18 European Champions Cup win over Wasps at the Sportsground.

The Irish province's Galway ground rocked to its foundations as Carty sent over the decisive conversion from far out on the right, a kick which means Wasps, Toulouse and Connacht are now tied on 13 points each at the top of Pool Two.

Dai Young's side, who were 32-17 winners at home last week, were on course for a double when they won a scrum against the head and Dan Robson fed Josh Barrett for a 72nd minute try.

That came after two Jimmy Gopperth penalties which had erased Connacht's 13-7 half-time lead, the hosts ending the first half with a Danie Poolman try from fly-half Carty's cross-field kick.

But the vast majority of the 8,090 crowd were delighted with Connacht's late sprint finish, a last-gasp maul seeing Fijian newcomer Dawai plunge over on his debut. It was left to Carty to decide the outcome and the 24-year-old nailed the difficult kick before being enveloped by his team-mates.

Having missed his first place-kick of the night, Carty redeemed himself with a well-struck 42-metre penalty in the eighth minute, rewarding Quinn Roux's graft at the breakdown.

But the hosts' midfield was opened up by Thomas Young, who was not held in the tackle, and his break - added to by the supporting Nathan Hughes - saw scrum half Joe Simpson finish off just to the left of the posts, with Gopperth converting.

Connacht were unable to profit from Carty's half-break and Wasps almost opened the second quarter with another try. Inspired by a John Muldoon poach, the hosts just about held them at bay from two close-in mauls.

The sin-binning of home full-back Tiernan O'Halloran for not rolling away was not as keenly felt as it should have been, the ever-threatening Matt Healy releasing Bundee Aki for a surge downfield. Ultan Dillane also got on the ball before a 31st minute penalty allowed Carty to close the gap to 7-6.

Although Wasps managed to even up the scrum battle and then force the issue later on, Connacht's forwards were packing more of a punch in the loose and off a cleverly-worked lineout, Carty's crafty cross-field kick out to the left bounced for the waiting Poolman to dot down.

An excellent touchline conversion from Carty sent the westerners into the second half on a real high, before Wasps' smart defence - led by skipper Joe Launchbury - marched Connacht back and Gopperth's 53rd-minute penalty reduced the arrears to three.

The hosts had most of the territory but were getting little change out of referee Jerome Garces. A harsh penalty considering Matt Mullan's angle of scrummaging was sent wide by Gopperth on the hour mark.

The New Zealander was back on target in the 67th minute to draw Wasps level, as the visitors' ball-carrying threat increased. Winger Bassett was hauled down short via a clever chip from Robson, Simpson's replacement.

Aki's counter-rucking skills won a relieving scrum for Connacht but Wasps, with Mullan allowed to come in on an angle, forced the turnover and Robson's inviting pass sent Bassett over in the left corner.

Gopperth was unable to convert, though, and Connacht's never-say-die spirit was rewarded in the dying seconds.

With Aki joining the maul, the hosts created enough momentum for Dawai to touch down and Carty, whose kicking form has been indifferent, answered his critics in the best possible way.