It took a second-half try from Callum Black - on the prop's 100th appearance which also brought his first score - to give Ulster the lead for the first time after they had trailed 5-3 at the break.

Replacement Paddy Jackson's conversion followed by a penalty - Ulster's only score of the first half had come from a Ruan Pienaar penalty - gave the home side their hard-earned victory.

But the reigning champions - without a win in the league since last November - snatched a late losing bonus point through an 80th-minute try from sub Taqele Naiyaravoro which came despite the fact that Gregor Townsend's men were down to 14-men.

It did not start too well for Ulster as Pienaar surprisingly missed a sixth-minute penalty which looked a certain three-pointer for the home side.

The Warriors did not hang around, though, and after Sam Johnson burst through in midfield winger Lee Jones was over in the corner for a well-taken ninth-minute score which Gregor Hunter failed to convert.

Ulster struck back, though, with Pienaar this time managing a 22nd-minute penalty and then the Springbok was denied a possible score by the TMO after Craig Gilroy's kick infield.

Pienaar left shortly afterwards with an injury and Paul Marshall's first act was to nearly score only for the TMO to rule that prop Sila Puafisi had got there first and that was as close as Ulster got to further eating into Glasgow's lead before half-time.

Ulster needed to do something and on 51 minutes Gilroy worked some magic to give Ulster rare territory and from the attack Black barged over with Jackson's conversion giving the home side a 10-5 lead.

That became 13-5 on 65 minutes through a Jackson penalty after another Gilroy run had put them in prime position.

The Warriors were then reduced to 14 men when number eight Ryan Wilson was yellow-carded but Ulster failed to score again leaving the last say to the visitors when sub Naiyaravoro went in.