Seven days on from the loss to Ospreys they were made to work hard for the win which brought with it an all-important bonus point.
Two tries from Robbie Diack and single scores from Rob Herring and Ricky Andrew along with three Ruan Pienaar conversions helped Ulster register their 13th league win from 15 games to keep them seven points ahead of Glasgow Warriors.
Ulster, with Ireland squad members Chris Henry, Iain Henderson, Declan Fitzpatrick and Paddy Jackson all back, started with urgency and after only seven minutes it looked as if Chris Cochrane was over in the left corner only for the television match official to adjudge the winger had a foot in touch.
Then Zebre's lineout throw at the corner flag turned out to be an overthrow and Herring gladly accepted a gift of an eighth-minute score which Pienaar converted.
Zebre put Ulster under pressure for a while in their own 22, with Daniel Halangahu kicking a 33rd-minute penalty to cut their arrears.
The only thing that was better than last week's game was the result.
Just as the game edged towards half-time though, Ulster struck back when an Andrew Trimble grubber kick was collected by Pienaar who did remarkably well before substitute Stuart Olding, on for the injured Luke Marshall, was hauled down short.
With Ulster moving the ball left, Diack drove over.
Pienaar missed the difficult conversion and Ulster trooped off 12-3 to the good. With John Afoa joining the action at the start of the second half in place of Fitzpatrick, Ulster's scrum immediately improved and the home side had another TMO call go against them when Henderson wasdetermined to have been short of the line.
Ulster scored again three minutes before the hour when Diack crossed under the posts from Darren Cave's offload after Trimble had made a great surge.
Pienaar's conversion made it 19-3 and the home side looked comfortable for the win with a bonus point very much in their sights.
It came in the 72nd minute thanks to a try from Andrew after Ulster attacked right from a scrum. Pienaar kicked the conversion.
Ulster finished with 14 men on the field after Johann Muller left the action with only four minutes left but they conceded no further points.
But following the match, Ulster coach Mark Anscombe said he was not happy with his side's "sloppy" performance and described their play as "poor.. horrible".
Anscombe added they need to improve before facing an on-form Glasgow side next week.
He said: "We turned the ball over 20 times in a game is a trend we do regularly and we're not getting any better and that's of concern."