The 32-year-old entered the field midway through the second half and shored up an impressive win for the two-try Warriors who were already bound for next season’s Heineken Cup.
Leading 6-3 at half-time thanks to current Welsh international Ceri Sweeney’s brace of penalties, the pride of Glamorgan struck twice after the restart through Tongan wing Aisea Havili and Sonny Parker to conclude the season with a fifth straight win.
One of 12 internationals in the side, Parker was elusive in the early stages and together with man-of-the-match Jon Bryant at inside centre, was to the fore of the Warriors’ greater attacking strength.
But Connacht took the lead after 12 minutes, which was to be the only time in the match.
The 35-year-old Eric Elwood, playing his 149th match for the western province, punished the loose hands of Warriors prop Chris Horsman to slot over from 22 metres.
Elwood, who has pledged his future to Connacht for another year, played for Ireland against a young Jenkins in Dublin over 11 years ago.
Connacht made a presentation to the ‘Ginger monster’ Jenkins before the game and it was the visitors who also took home the victory.
The presentation and the call for the bar to stay open until 1am raised the biggest cheers of what was to prove a listless night for home fans.
Sweeney booted the visitors in front before the half-time whistle as twice the Connacht back row infringed at rucks after 27 minutes and again after 36.
Connacht, with little to play for in eighth in the table, conceded directly after the restart as Bryant’s quick hands saw Havili scoot over on 47 minutes.
Havili had to evade the challenge of Ted Robinson before scoring to the right of the posts.
Sweeney added the extras and converted Parker’s effort in the 54th minute.
A telling break by the centre through a barren Connacht midfield with the aid of Gareth Thomas saw him cross with relative ease.
Jenkins’ arrival saw a couple of trademark skyscraper kicks but little to trouble either try line.