Paris - Six penalties from Irish flyhalf Jonathan Sexton were enough to give champions Leinster an 18-13 victory away at Bath in their European Cup Pool 3 match on Sunday.
Victory saw Leinster - who have lost just two of their last 19 European Cup matches - top the table after four matches and looking forward to the visit of Bath at Lansdowne Road next weekend where they have already sold over 40 000 tickets.
Scottish side Glasgow are in second three points behind the Irish side after they edged a second string Montpellier 20-15 in Glasgow in an ill-tempered affair that saw three players sin-binned.
Four penalties from Glasgow's highly-thought of 20-year-old flyhalf Duncan Weir provided the hosts with the backbone of their victory.
Leinster and Bath both had chances to score tries in the opening 10 minutes - Sexton setting up a brilliant move from deep inside their own half which came to grief only yards from the Bath line.
Bath, though, also threatened the champions line after a great break through the centre by Matt Banahan but again the hosts were unable to finish it off and Leinster eventually cleared the ball.
Leinster spurned a terrific chance to cross the tryline just before the quarter hour mark as Irish fullback Rob Kearney chose the wrong option in passing inside rather than outside where there was a clear run for Isa Nacewa and the move broke down.
Bath went back up the other end and Olly Barkley broke the deadlock with a crisply struck penalty to break Jonathan Callard's European Cup points record for the English club.
He was to add another penalty five minutes before the break as the hosts threatened to cause a major surprise and their morale was boosted further when Sexton sent a penalty wide of the far post.
However, the Irish star - Man-of-the-Match in last season's come-from-behind final win over Northampton - did convert one in stoppage time of the first-half.
Leinster came out with a bang in the second-half and Sean O'Brien went on a rampaging run deep into the 22 breaking several tackles but was stopped just short but while the Irish side failed to come away with a try Sexton was inch perfect with a penalty to draw them level.
However, the visitors' exhilarating attacking play was not matched by their finishing as shortly afterwards a superb kick and collect by Nacewa set them up brilliantly but O'Brien somehow fouled things up when he had a three to one overlap.
Sexton, though, made no such mistake to finally give them the lead in the 55th minute with another penalty and landed another on the hour mark after a scintillating break by Nacewa had set it up but Bath hit back in style.
Leinster turned the ball over and the hosts took full advantage as they set up Banahan for his 50th try for the club - Barkley converted to put them 13-12 ahead.
Sexton, though, gave Leinster the advantage once again with eight minutes remaining after an infringement by Springbok Francois Louw - who had been instrumental in forcing the Leinster turnover which led to the try - and the latter muddied his copybook further two minutes later when he was sin-binned.
Sexton added a penalty on the final whistle to round off a satisfying day's work.
European Cup results on Sunday:
Bath 13 Leinster 18
Glasgow 20 Montpellier 15
Clermont 30 Leicester 12
Played on Saturday:
Castres 41 Northampton 22
Scarlets 14 Munster 17
Racing Metro 14 London Irish 34
Treviso 30 Biarritz 26
Saracens 31 Ospreys 26
Connacht 10 Gloucester 14
Played on Friday:
Cardiff Blues 25 Edinburgh 8
Ulster 31 Aironi 10
Harlequins 10 Toulouse 21