Monfils, the No. 3 seed, posted a 7-6 (7-2), 2-6, 6-4 triumph over fellow Frenchman Jo-Wilfried Tsonga, while Ljubicic prevailed over Spain's Albert Montanes in a 6-3, 7-6 (7-4) decision.
Monfils, 24, advanced to his third final of 2010 after producing the only break of the third set, beating his countryman for the first time in three meetings. Second-seeded Tsonga had downed Monfils in semifinals at Bangkok in 2008 and Tokyo last year.
Ljubicic, meanwhile, ripped off 18 aces during his 77-minute match and won 91 percent of the points on his first serve.
The Croatian is the Sud de France defending champion.
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