Henry's try on the hour mark finally put some breathing space between Ulster and the Warriors after the sides had been just three points apart for the first 59 minutes.

Ulster led 6-3 at the break as a brace of Jackson penalties replied to Peter Horne's 20th-minute opener.

Scoring chances were hard to come by at Scotstoun but both teams missed two kicks at goal in the opening period, before Horne was off target with a third just two minutes after the interval.

Ruan Pienaar's second attempt at the posts experienced the same fate as his first on 58 minutes but Henry's touchdown finally had the scoreboard moving again just moments later.

Having been awarded another penalty directly after the restart following Pienaar's long-range miss, Ulster opted to kick to touch, duly won the lineout and powered towards the line. Openside flanker Henry was the man to emerge with the ball in his grasp but the whole pack deserve credit for the critical score.

Jackson's conversion made it 13-3 and, when the young fly-half added a penalty two minutes further down the line, Ulster were suddenly in complete control.

A fourth three-pointer from Jackson had Ulster 16 points to the good with five minutes remaining and a 77th-minute unconverted try from Niko Matawalu was only minor consolation for Glasgow.