In-form Harlequins were given a Heineken Cup scare by Connacht but still managed to start their European campaign with a 25-17 victory.
The Aviva Premiership Rugby leaders extended their perfect record this season to a perfect 11 from 11 in all competitions despite being outscored by two tries to one at Twickenham Stoop. Karl Dickson crossed the line for the hosts but, as is often the case, the boot of Nick Evans proved to be their greatest weapon as the fly-half was responsible for the rest of their points.
Connacht, who were playing in their first Heineken Cup match, scored tries through Tiernan O'Halloran and Gavin Duffy and will feel aggrieved to have not secured at least a losing bonus point.
Evans got Quins on the board in the sixth minute as he comfortably slotted over a penalty from the right of the posts, but Connacht's Miah Nikora hit back with three points of his own two minutes later.
The early kicking battle continued on nine minutes when Evans nailed his second attempt from beyond the 10-metre line. But surprisingly it was the visitors who got the first try on the board when Eoin Griffin dummied his way through the defensive line before playing in O'Halloran for the try, with Nikora converting.
Quins responded with some heavy pressure of their own but only managed to cut the gap by three points after Evans put a penalty through the posts while missing another from long-range.
The hosts continued to dominate territory and possession, though, and Connacht's resistance finally gave in as Dickson powered over the try-line from close range, with Evans' conversion making it 16-10. The lead was extended to nine points before the half-time interval as Evans was successful with another penalty after Chris Robshaw had been the victim of a high tackle.
The Irish outfit made an encouraging start to the second half but the quality of Quins seemed to be telling as they asserted themselves in Connacht territory once again. However, it was Connacht who had the first chance to get points on the board after the interval but replacement fly-half Niall O'Connor could not find the target.
And the away side were in for their second try in the 58th minute, with Brian Tuohy the creator as his fine looping pass allowed former Quins player Duffy to cross, with O'Connor adding the conversion. The momentum was now completely with Connacht and only a brilliant tackle from Seb Stegman prevented another try moments later.
Harlequins wing Sam Smith was then denied a score by the video referee as he attempted to ground in the corner and Connacht responded by probing at the other end. But the hosts survived and Evans settled the nerves with a penalty to make it 22-17 and the New Zealander then slotted over another three points in the dying stages to cruelly prevent the visitors from picking up a losing bonus point.