Ulster survived a last-quarter fightback by visiting Northampton to win 27-22 and start their Champions Cup campaign with two victories.
Rob Herring, Ethan McIlroy and Craig Gilroy scored tries as the hosts built a 15-point lead by the 57th minute.
Alex Mitchell and Courtnall Skosan hit back with tries for Saints but Ulster halted their final drive.
Ulster took the lead after two minutes as hooker Herring charged over from close range with scrum-half John Cooney adding the conversion.
Saints replied with a George Furbank penalty.
Ulster were awarded a penalty try on 16 minutes when Mitchell was adjudged to have deliberately knocked on trying to intercept a pass to McIlroy. The Saints scrum-half was also yellow-carded and seven points awarded.
Furbank kicked another penalty, but Ulster again replied with a try as 21-year-old McIlroy sidestepped the last defender and then powered over the line at the second attempt.
Furbank kicked two more penalties before the half hour but Cooney landed a penalty early in the second half.
Ulster scored their bonus-point try on 58 minutes after Saints full-back Ahsee Tuala misjudged a Billy Burns kick and Gilroy pounced to touch down.
The Saints fought back.
Mitchell sniped over for an unconverted try two minutes later and winger Skosan finished a slick handing move with two minutes remaining.
Furbank failed to convert, meaning a try was still required, and England captain Courtney Lawes was penalised as Saints chased that last-minute winner.
The evening's other scheduled match was one of a raft of games this weekend hit by the Covid-19 spike.
Leinster were unable to send a team to France because of the number of cases in their squad and Montpellier were awarded a 28-0 walkover
