LONDON (Reuters) - Munster secured a quarter-final place in the Heineken Cup with a hard-fought victory over French club Castres Saturday while also in Pool 1 Northampton moved into second spot by beating Llanelli to keep their slim hopes of a last-eight place alive.
Munster's Ronan O'Gara became the most capped player in the Heineken Cup with his 102nd appearance and marked the occasion by scoring 16 points with his boot to lead his side to a 26-10 home victory.
Last year's beaten finalists Northampton trailed 14-6 at halftime but hit back after the interval to win 29-17.
Scarlets went into the match in second place in the pool and sensing a first quarter-final place since 2007 was in reach but were outplayed in the second half.
Prop Soane Tonga'uiha powered over early in the second period as the visitors began to exert some control and Ben Foden scored a breakaway try late on to kill off the Scarlets.
Northampton need to beat Munster convincingly next week to stand any chance of being one of the best runners-up.
Ulster crushed Leicester Tigers 41-7 in Belfast to stay top of Pool 4 with two tries from Andrew Trimble and one each from Craig Gilroy and Paul Marshall.
Clermont Auvergne enjoyed an 82-0 romp at Italian side Aironi to maintain their hopes of a quarter-final spot going into the final round of group fixtures.
The French club ran in 12 tries to set up a winner-takes-all clash with Ulster next weekend. Wings Sitiveni Sivivatu and Julien Malzieu scored try hat-tricks.
In Pool 6 Harlequins ended Gloucester's chances with a 20-14 victory which means top spot in the group will be decided next week when leaders Toulouse face Gloucester and Harlequins go to Connacht knowing they have to win.
Toulouse beat Connacht 24-3 at Stade Ernest Wallon.
Friday Edinburgh retained top spot in Pool 2 with a last-gasp 27-24 victory away to Racing Metro sealed by a drop goal from Phil Godman.
The six pool winners and the two best second-placed teams advance to the quarter-finals.
(Reporting by Martyn Herman; Editing by Ken Ferris)