Ulster's already slim chances of making the Heineken Cup quarter-finals were given the lifeline they needed with this bonus point win over London Irish.

Maximum points were essential to give Mark McCall's squad any hope of European survival and Paul Steinmetz's 76th minute try gave the home side the all-important boost ahead of leaders Llanelli's game at Toulouse tomorrow, a game the French side must win to set up a nail-biting finish for qualification.

After losing their way in an almost panic-stricken first-half performance, Ulster rediscovered their composure and, with David Humphreys grabbing an opportunistic second-half try, made up for their collapse at London Irish last week.

The Ravenhill encounter was certainly a tempestuous affair with four players, two from each side, ending up in the bin, but Ulster had the nerve to get what they needed.

Ulster showed their intent from the off when opting to kick for the corner instead of aiming at the posts but they failed to capitalise and began to show an alarming lack of precision in attack and defence.

It was little surprise that Irish opened the scoring with a Shane Geraghty penalty, after 14 minutes, shortly after a Paul Hodgson kick and chase could have resulted in the visitors grabbing an early try.

The home side, desperately seeking a bonus point win, did put together a brief passage of constructive go forward ball when, from a scrum, Humphreys cross kicked for Andrew Trimble to bounce two defenders and make the left corner. Referee Christophe Berdos failed to be entirely convinced and went upstairs to the third match official who allowed the score.

Humphreys missed the difficult conversion but Ulster's performance deteriorated further with the 26th-minute sin binning of Isaac Boss after a high hit on Delon Armitage.

Still Ulster only managed to ship three points through another Geraghty penalty on the half hour - he had missed his earlier attempt from Boss' binning - which gave Irish a 6-5 lead.

Ulster's only response before the break was far from encouraging as Steinmetz missed a drop goal attempt and then Humphreys was wide with a penalty.

The veteran out half certainly made amends four minutes after the restart when, after shaping up to take a penalty but not indicating that he actually would, Irish turned their backs and Humphreys tapped the ball to himself and dashed over in the left corner. He then nailed the conversion.

With the home side now exerting the sort of control that eluded them earlier, Humphreys stretched the lead to 15-6 after 49 minutes and then, two minutes before the hour, substitute Neil McMillan crossed for a converted try after Justin Bishop had fumbled a Paddy Wallace chip.

Irish did strike back with a Gonzalo Tiesi try, just after the hour, but Ulster closed the deal shortly afterwards. With Bob Casey in the bin, Steinmetz grabbed the vital bonus point try. Humphreys converted to make it 29-13 and all that remained was the late binning of Trimble and Armitage for fighting.