The victory, Glasgow’s fourth in a row, moves Danny Wilson’s side to the top of the table but they must now wait and see how Benetton and Munster fare in their final matches next weekend.
The winners of the northern section of the Rainbow Cup will play the top-ranked South African team in the final in Italy on June 19.
“Just outstanding, from my point of view,” said a delighted Wilson. “The boys rocked up again with huge emotion, really physical. We set our minds on beating Leinster, and to finish the main part of the season by beating Leinster is an outstanding reflection of how these boys have really turned the corner in the last four or five weeks.”
It was a fitting way for a number of the Warriors players to say farewell to Scotstoun. Adam Hastings, Niko Matawalu and D’arcy Rae were all playing their final home games for the club and they were given the perfect send off.
But it was a niggly game, punctuated by three yellow cards and numerous stoppages as referee Frank Murphy tried to maintain order.
Hastings in particular seemed to be singled out by the visitors for rough treatment and the full-back did well to keep his cool in the face of sustained provocation.
Glasgow made early headway and placed the Irish side under a period of sustained pressure which yielded the game’s first try. Fraser Brown took a quick tap and go and Matt Fagerson eventually managed to burrow his way over.
Ross Thompson kicked the conversion to take his points haul for Glasgow to 100 points, becoming the quickest in the club’s history to reach the milestone.
Leinster’s response was immediate, with scrum-half Luke McGrath squeezing through a gap between Hastings and Rory Darge to run under the posts after good work by Josh van der Flier and Calean Doris. Ross Byrne added the extras to tie things at 7-7.
Midway through the first half, Leinster thought they had extended their league but Hugo Keenan’s impressive ‘try’ was chalked off for an earlier knock on.
Glasgow then lost Sam Johnson to a knock, with Stafford McDowall replacing the centre.
More injurious for the home side was the yellow card shown to Cole Forbes in the 26th minute. The Warriors winger was guilty of pulling Kelleher’s jersey and the visitors made the most of the numerical advantage with their second try.
The ball was moved out the line smartly and Cian Kelleher stepped inside George Horne and Brown to finish impressively. Byrne’s conversion attempt struck the upright.
Leinster found themselves reduced to 14 when Rory O’Loughlin was shown yellow just before the interval.
Keenan’s luck deserted him again in the early minutes of the second half when he had a second try disallowed. The Leinster full-back cantered in from halfway but sub Andrew Porter was correctly adjudged to have obstructed Rob Harley, creating the gap for Keenan to run through.
Glasgow took full advantage and drew level with an impressive score which had much to do with Hastings’ sleight of hand. The full-back had taken the ball from Forbes, then showed good strength before flicking the ball out to Kyle Steyn who scored the try. Thompson missed the kick but the Warriors were back in the game at 12-12.
The match was becoming increasingly fractious and Ryan Wilson was yellow carded for a neck-roll offence. This sparked more argy-bargy with Hastings once again a target for the Leinster players who were clearly bearing a grudge against the Glasgow player who was sent off when the sides met in Dublin in February.
Glasgow edged ahead in the 64th minute when Thompson was straight and true with a long-range penalty which proved to be the match-winning moment.