French giants Montpellier suffered a shock home defeat to Exeter in Leinster’s Champions Cup pool.
Irish assistant referee Joy Neville became the first female official to be involved in a Champions Cup clash as she took her place on the sideline.
Leo Cullen’s men top the table after two bonus-point wins but today’s result leaves the Top 14 outfit with just three points after two games, and playing catch-up in the race for quarter-final spots.
Leinster will travel to France in round 6 and although French sides usually perform better at home, there is now the real possibility that their interest in Europe may wane and be non-existent should a quarter-final spot be out of reach at the end of January.
Montpellier are currently in second place in the Top 14.
Leinster’s next Pool 3 game is away to Exeter on 10 December before the return leg six days later at Aviva Stadium.
The Chiefs made it back-to-back Champions Cup wins as they claimed a famous victory.
Don Armand scored a try in each half, while former Ireland centre Ian Whitten also added a try as Ulster man Gareth Steenson kicked three conversions and two penalties for the best European result in Exeter's history.
Nemani Nadolo crossed twice for Montpellier and Joe Tomane and Benoit Paillaugue also added scores, but it was not enough to stop Rob Baxter's men from celebrating.
Former Ulster scrum-half Ruan Pienaar had to be taken from the field on a stretcher wearing a neck brace following a collision with team-mate Jesse Mogg.
The home side secured two points for scoring four tries and finishing within seven of Exeter, but it is the English outfit and Leinster who are both unbeaten in Pool Three.