An under-strength Ulster maintained their 100% record in the Pro12 with an unimpressive win over Zebre in Parma.
The leaders were outscored four tries to two by the bottom side but snatched victory with a late penalty try.
Zebre earlier punished a slack Ulster with tries from number eight Andries Van Schalkwyk (two), and half-backs Tito Tebaldi and Daniel Halangahu.
Paddy Wallace edged Ulster ahead with a 58th-minute try but Zebre got their noses in front until the penalty try.
Ulster had been putting Zebre under pressure close to the line and referee Neil Patterson penalised the home side, believing they had stood up at a scrum when a try would otherwise have been scored.
That levelled the game at 25-25 and fly-half Niall O’Connor, who had a decent day with the boot, had the simple task of sealing the victory with the conversion in front of the posts.