Paris - Ulster came from behind to beat Wasps 19-9 on Friday as the European Champions Cup got underway at Belfast's Kingspan Stadium.
Ulster were trailing 9-3 early in the second half but tries from winger Jacob Stockdale and centre Stuart McCloskey lifted the hosts past their English visitors in this Pool 1 clash.
An ex Wasps player Charles Piutau set up Stockdale's score with two minutes later Piutau and Stockdale combining before McCloskey barged over.
On-loan Christian Lealiifano, the Wallaby fly-half who was diagnosed with leukaemia last year and had a bone marrow transplant, produced two late penalties to deny Wasps a losing bonus point.
Two penalties from Jimmy Gopperth and one from Elliot Daly had put Wasps in front at the break after new arrival John Cooney's penalty for the Irish province, winners of the competition in 1999.
"We're very happy with the result but it's just one game down and there's a long way to go," said Ulster coach Les Kiss.
This was always going to be a tough assignment for two-time European champions Wasps, struggling in the English Premiership, only five days after their 38-19 league mauling by Saracens and with 15 players out injured.
Saracens, kings of Europe for the last two years and top of the English Premiership, make their bow on Sunday away to domestic rivals Northampton.
Saracens not only defended their title last season but also set a new record of 18 European matches in a row unbeaten as they defeated Clermont, the French champions, 28-17 in the Edinburgh final.
Getting off to a good start will be vital in a pool that includes Clermont -- beaten finalists in three of the last five years -- and Ospreys.