Chris Whitaker lands the first try for Leinster against Agen
Leinster (10) 26
Tries: Whitaker, O'Driscoll (3).
Pens: D'Arcy (2)
Agen (0) 10
Skipper Brian O'Driscoll scored three tries as Leinster toppled Agen from the top of Pool Four with a bonus-point victory at Lansdowne Road.
Former Waratahs skipper Chris Whitaker got Leinster off to a great start with a try inside four minutes.
Ireland captain Brian O'Driscoll raced away for a try on 12 minutes and added another midway through the second half.
Winger Rupeni Caucaunibuca scored a late try for Agen but O'Driscoll had the final say right at the end.
Whitaker's opening try came after Stephen Keogh bulldozed through. He was held up short but the Australian scrum-half snapped on to the ruck ball and dived over.
O'Driscoll showed his class on the quarter-hour when he intercepted Agen fly-half Jerome Miquel and raced a full 70 metres, fending off Caucaunibuca, to score in the right corner.
Agen ended the half on the up as some powerful play from their pack saw Miquel reduce the gap with a close-range penalty.
Gordon D'Arcy took over the kicking duties from Girvan Dempsey and cracked over an easy effort on 51 minutes to re-establish a seven-point lead for Leinster.
The Ireland centre added a second penalty shortly after the hour and Leinster's win was confirmed on 66 minutes when O'Driscoll spun in for his second try.
D'Arcy missed the conversion and Agen made a fight of it when three minutes later, Caucaunibuca ran in a try on the left.
Leinster's bonus point try came when a long pass from Malcolm O'Kelly gave O'Driscoll the space to make the corner again.
Leinster: Dempsey, Horgan, O'Driscoll, D'Arcy, Hickie, Warner, Whitaker, McCormack, Blaney, Wright, Hogan, O'Kelly, Keogh, Gleeson, Heaslip, Jowitt.
Replacements: Lewis for O'Driscoll (80), Fitzgerald for Hickie (73), Easterby for Whitaker (69), Corrigan for Wright (41), Jowitt for Keogh (67), Finegan for Jowitt (75).
Agen: Elhorga, Mirande, Stoltz, Ahotaeiloa, Caucaunibuca, Miquel, Morlaes, Guinazu, Tiatia, Meeuws, Stolz, Socol, Lievremont, Ostiglia, Fonua.
Replacements: L. Cabarry for Guinazu (65), Badenhorst for Socol (45), Culine for Ostiglia (50), Galasso for Fonua (80).
Referee: Wayne Barnes (RFU).