Defending champions Leinster were left clinging on for a nervy, narrow win over Heineken Cup debutants Exeter Chiefs. Argentina international Ignacio Mieres missed an injury-time penalty which would have earned a draw for Exeter but Jonathan Sexton's nine-point haul proved to be just enough for the 2009, 2011 and 2012 winners.
Led by man-of-the-match Tom Hayes, the Chiefs played the better rugby for much of this tryless Pool 5 opener and looked right at home in Europe's top tournament. However, fly-half Gareth Steenson missed two of his four penalty attempts as his opposite number Sexton helped Leinster squeeze home.
Sexton was off target with his first shot at the posts, but converted his second after Hayes, the Exeter captain, had been caught offside.
There was a breathless start to the match, with both sides building off quick ruck ball and some strong carrying from the forwards.
Steenson flicked a penalty effort to the left and wide before Exeter enjoyed their first productive spell as Jason Shoemark, Ian Whitten and Simon Alcott all made good ground.
The visitors were finding space on the flanks and Leinster's Ian Madigan, starting at full-back for the injured Rob Kearney, was tested by a kick to the right corner as Matt Jess closed him down.
Leinster were able to absorb Exeter's advances and Steenson suffered a second penalty miss, lacking the direction on a long-range attempt.
Nevertheless, the hosts were forced back on the defensive and severely starved of possession. Haydn Thomas's quick deliveries kept Exeter moving forward and they ended the half with a two-thirds share of the possession.
Rob Baxter's men managed to level the game on the stroke of half-time too, Steenson splitting the posts after the Leinster front row had popped up in a scrum. The home side improved in the third quarter, Richardt Strauss and Jamie Heaslip driving forward with Sexton and Eoin Reddan wielding more influence.
Sexton restored Leinster's lead with a 54th-minute penalty, however his kicking radar was off five minutes later and Exeter soon grinded their way downfield,
Sireli Naqelevuki and Dean Mumm adding their weight to the attack and a ruck offence allowed Steenson to kick them level with 15 minutes to go. A wind-backed Madigan then watched his monster drop goal effort go past the right-hand post.
Better ball retention during a short rain shower got Leinster back within scoring range, and it did the trick as Exeter replacement Ben Moon tackled from an offside position and Sexton slotted the central penalty to make it 9-6.
Leinster had to endure a nervous final few seconds as Steenson's replacement, Mieres, lined up a last-gasp penalty from just inside the Leinster half. The Argentine's kick missed to the right though, and the losing bonus point was Exeter's only reward.
Leinster's head coach Joe Schmidt heaped praise on Exeter, saying: "It was no surprise to us how tough they were to break down. They are greater than the sum of their parts. I just think they are a very unified group. They're well coached, they're well organised and they're hard to break down."
His opposite number Baxter said: "There was a little bit of everything in the game. We're a little bit unfortunate not to come away with a win or a draw. We still made some mistakes that cost us a chance of what would be a very, very important win."
Leinster Madigan, Conway, O'Driscoll, McFadden, Nacewa, J. Sexton, Reddan, Healy (Van der Merwe, 52), Strauss (Cronin, 73), Ross, Cullen, Browne (Toner, 52) McLaughlin, Jennings, J. Heaslip.
Exeter Arnott, Whitten, Dollman, Shoemark (Naqelevuki, 54) Jess, Steenson (Mieres, 65), Thomas (Chudley, 54), Sturgess, Alcott (Whitehead, 65), Rimmer (Budgen, 75), Hayes, Hanks (Muldowney, 71) Johnson (Mumm, 58), Scaysbrook, Baxter.
Referee Pascal Gauzere (France).
Pens: Sexton (3)
Pens: Steenson (2)