|Glasgow Warriors (7) 17|
|Tries: Reid, Seymour Cons: Russell 2 Pen: Russell|
|Ulster (15) 22|
|Tries: Cave, Pen, Jackson Cons: Jackson 2 Pen: Jackson|
Ulster moved top of the Pro12 as Glasgow suffered a second consecutive loss in a brutal contest at Scotstoun.
A first half which saw four players depart injured, two Ulster tries disallowed and two yellow cards ended with the visitors leading 15-7.
Darren Cave finished a flowing move but Gordon Reid dived over for Glasgow.
A controversial penalty try extended Ulster's lead but Tommy Seymour's score saw Glasgow nudge ahead before the hour but Paddy Jackson's try prove decisive.
Glasgow derailed by Piutau express
Ulster's dominance for much of the game was vast.
Jackson's early penalty put them ahead and even when Iain Henderson was sin-binned for a dump tackle on Tommy Seymour, they extended their lead.
Ulster's All Black wing Charles Piutau was at the heart of so much of their attacking. He did Stuart Hogg for pace, then he carried again, racing away from Leonardo Sarto up the left wing. When Ulster swept right, Cave went over.
Reid's try - from a yard out - and Russell's conversion, on his 24th birthday and his return to the team after that awful injury at the end of last season, narrowed the gap to 7-8.
Still, Ulster's control continued to the break. They were wrongly denied a try when Rob Herring's score was ruled out for a Henderson obstruction, but they came again.
Piutau caused more havoc. Another break and then another, which saw Sarto penalised, wrongly, for a dangerous tackle as the New Zealander honed in on the try-line.
Referee Ian Davies gave the penalty try and sent Sarto to the bin for good measure. Jackson converted for a 15-7 half-time lead.
Comeback typifies Warriors' character
Ulster had 70% possession in the opening half and all the big ball carriers were in the Ulster ranks.
They might have gone further ahead on the resumption but Seymour knocked the ball out of Jackson's hands after a slashing break from the fly-half, but play went back for an earlier offside and the tide began to turn.
Russell made it 15-10 with a penalty and then Hogg drew the cover beautifully before putting Seymour over in the corner for his seventh try of the season. Russell converted to put Glasgow ahead.
At that point, just short of the hour, Glasgow had had only 38% possession in the entire match and yet they were two points clear.
It was utterly illogical but it typified their character and their predatory instincts. Glasgow made a little ball go an awfully long way.
Ulster's class prevails
Jackson's try was delicious; an attack that sliced through the heart of the Glasgow defence. The fly-half converted to restore the five-point lead. Having regained their advantage they then defended like demons to protect it.
Ulster have had some painful losses here in the past. They wouldn't be denied this time.
Not many teams get out of Glasgow with a win in the Pro 12. Ulster did - and they deserved it.
Glasgow Warriors: S Hogg, L Sarto, M Bennett, A Dunbar, T Seymour, F Russell, H Pyrgos (co-captain); G Reid, F Brown, Z Fagerson, G Peterson, J Gray (co-captain), T Uanivi, L Wynne, R Wilson.
Replacements: C Flynn (for Peterson, 23), A Allan (for Reid, 29), S Puafisi (for Z Fagerson, 51), S Thomson (for Uanivi, 31), M Fagerson (for Wilson, 71), A Price (for Pyrgos, 72), N Grigg (for R Hughes, 76), R Hughes (for Sarto, 48).
Sin-bin: Sarto (38)
Ulster: J Payne, L Ludik, D Cave, S McCloskey, C Piutau; P Jackson, R Pienaar; A Warwick, R Herring (captain), R Ah You, A O'Connor, F van der Merwe, I Henderson, S Reidy, R Wilson.
Replacements: R Best (for Herring, 49), C Black, R Kane (for Ah You, 54), P Browne (for O'Connor, 55), C Ross (for Wilson, 59), P Marshall, S Olding (for McCloskey, 14), R Lyttle (for Olding).
Sin-bin: Henderson (9)
Referee: Ian Davies (WRU)