Matt Williams' men, 12-0 winners over the Scots at Ravenhill last month, built up a 20-6 half-time lead thanks to quick-fire tries from David Pollock and Simon Danielli and ten points from the boot of full-back Clinton Schifcofske.

Thom Evans' ninth try of this season's league, converted by Colin Gregor, and a penalty brace from Parks set up a grandstand finish - however Ulster squeezed home to close the gap on fifth-placed Glasgow to a single point.

Warriors coach Sean Lineen said afterwards: "It was soul destroying. Our discipline cost us. We gave away two soft tries when Moray Low was sent to the sin-bin.

"I was proud of the way the players came back, they really stuck in there.

"We could've won that game with the last kick of the game but it was lost long before then."

Lineen selected an unchanged team, keeping faith with the side that ran in six tries against the Scarlets a fortnight ago. Ulster have one notable change with Grand Slam flanker Stephen Ferris back in the starting line-up after recovering from a hand injury.

Amidst an error-strewn start from both sides, Ferris helped tee up an early penalty shot for Ulster out-half Niall O'Connor but his effort from long range fell wide.

The Glasgow forwards replied with some punchy play, only for Gregor's opening penalty to miss the target. From closer in, the Glasgow out-half made no mistake to give his side an eighth-minute lead.

Neither side had settled into a rhythm before Schifcofske responded with a fine 40-metre penalty on the quarter-hour mark.

The first real attack of note came from Thom Evans, the league's top try scorer, as he glided into space and set up ruck ball in a good position.

Carlo Del Fava infringed for the visitors and Gregor mopped up with his second successful kick for 6-3 but again Schifcofske answered back in quick fashion, punishing some sloppy play from the Glasgow forwards.

The second Evans brother, Max, ignited a promising Glasgow attack with an excellent line break but again the home crowd were left frustrated when the ball was swung to both wings before Ruaridh Jackson missed a drop goal attempt.

Then came one of the game's defining moments. Glasgow prop Moray Low was sin-binned for hands in the ruck and Ulster put immediate pressure on by kicking a penalty to the corner.

Del Fava claimed the lineout and while Glasgow failed to wilt during a series of subsequent scrums, good work from Robbie Diack and the lively Paul Marshall helped Pollock crash over the line on an angled run.

Schifcofske converted and less than two minutes later, Ulster were celebrating their second try. Scotland winger Danielli scorched over on a trademark run, edging past Lome Fa'atau for his third touchdown in five league games.

Schifcofske converted and Glasgow's hopes were hit further when they lost inspirational captain Alastair Kellock to injury.

As Low return from the sin-bin, Ulster prop Bryan Young took his seat on the sideline for a yellow card offence. But Ulster breathed a sigh of relief when Jackson missed a monster penalty attempt in first half injury-time.

20-6 in arrears at the break, Glasgow raced out of the blocks for the second half and Thom Evans was over for his try within three minutes of the restart.

Marck McMillan and John Barclay made some early gains before a poor Ulster clearance kick allowed Barclay send Evans shuttling through and he beat four tacklers to score in the corner, with Gregor adding a superb conversion from wide out.

Both coaches looked to their benches for added impetus and Glasgow looked to have the greater momentum, with their forwards keeping Ulster pinned back and Parks' boot increasing the pressure on the scoreboard.

Ferris and company kept making the big hits, though, and thanks to some disciplined defending the Ulster try-line remained intact during a concerted bout of Glasgow attacking.

Parks, on for Jackson, made no mistake with a 20-metre penalty, pulling it back to 20-16.

Ulster tried to build an attacking platform but Glasgow were getting the run of the ball and with skipper Rory Best pinged for delaying a lineout throw and Ferris dropping a pass in midfield, the Scots were quickly back on the front foot.

Replacement centre Darren Cave was next into the sin-bin for a deliberate knock-on near the Ulster whitewash and after a flurry of ruck action, Parks landed his second penalty for 20-19.

Indiscipline left Ulster hanging on at the death and as they tried to retain possession and close out the win, they were penalised for coming in at the side and Glasgow motored back towards the whitewash.

Fa'atau was hauled down just short and Ulster's prayers were answered when Parks missed an 84th-minute penalty attempt from wide out on the left, with the kick veering away at the last moment.
Frustration for Glasgow and elation for Ulster, particularly so for young centre Ian Whitten who put in another impressive display.