A much-improved Leinster lost their second BKT URC match in a row, going down 39-31 to the Bulls in an 11-try thriller in Pretoria.
It's the first time since 2003 that Leinster have opened their season with consecutive losses in the competition.
They trailed 22-10 at half-time but two tries at the start of the second half put them in pole position. However, it was the hosts that finished stronger to claim a bonus-point win.
Leo Cullen’s side, who lost 35-0 to Stormers last weekend, took a try-bonus point but having led with just over 10 minutes left, they will be disappointed not to get a first ever win away at Loftus Versfeld.
It was Johan Ackermann’s side who got off to a perfect start when Keagan Johannes cross-kicked for Sebastian de Klerk to score in the corner.
Leinster were then made to pay for some loose defending when De Klerk ran from his own half, beating three defenders, before spinning the ball to centre David Kriel, who raced home.
Sam Prendergast kicked a penalty in thr 20th minute for Leinster's first points of the season, but the visitors lost Will Connors to the sin-bin for a head on head challenge on JJ Theron.
However, that led to a spell of possession for the defending champions and Thomas Clarkson barged his way over following a close-range tap and go penalty.
Two scrum penalties at the end of the half cost Leinster dearly with Johannes kicking a penalty before Bulls grabbed a third try with the last play.
This time flanker Mpilo Gumede finished under the posts when Leinster ran out of defenders.
Cullen’s side came out of the blocks after the break and were soon ahead with Hugh Cooney crossing after a spell of pressure close to the line.
Two minutes later, Tommy O’Brien (above) finished off a length-of-the-field move, with Prendergast converting both tries to hand Leinster a 24-22 lead.
Replacement Willie le Roux made an immediate impact and scored superb try that started in the Bulls 22.
The 36-year-old exchanged passes with Devon Williams and beat Prendergast to the line.
Leinster hit back, with John McKee and Jack Boyle to the fore. The pack forced two scrum penalties and Scott Penny bundled his way over from close range.
Prendergast’s conversion put Leinster four ahead but after they failed to take the restart, two cross-kicks opened up the defence and Stravino Jacobs scored in the corner.
Still Leinster had chances and Prendergast’s dropgoal from halfway had the distance but missed the target.
Having to force a play deep in their own half, Prendergast risked a pass wide that was picked off by Kriel, who scored his second.
The Ireland out-half was given a shot from halfway for a losing bonus point but his penalty missed and Leinster, who host the Sharks next weekend, remain winless.
