With its veteran point guard Mike Bibby struggling once again, the Heat called upon Mario Chalmers to pick up the slack off the bench. Chalmers delivered on both the offensive and defensive ends Tuesday night to give the Heat some impressive point guard production during a 92-84 victory in Game 1 of the NBA Finals. Chalmers played 27 minutes, finishing with 12 points including three timely three-pointers in the first half. But his second-half contributions, especially on the defensive end, helped the Heat neutralize Dallas' talented backcourt. Chalmers, who won a national championship at Kansas, said he was a bit nervous playing in his first NBA Finals game. "I couldn't even take my pregame nap or anything," Chalmers said. "I had some jitters. But I just said to myself, keep shooting and relax." Bibby started the game — his 16th start in 16 playoff games so far for the Heat — but struggled. Although Heat coach Erik Spoelstra has felt comfortable letting the veteran run the Heat's offense, it was clear Chalmers provided the Heat with a boost of energy when it needed it most Tuesday.