Before the Celtics kicked off their seven-game winning streak with a double-overtime win over the Miami Heat on Jan. 27, Paul Pierce hadn’t had a triple-double since the winter of 2010. He’s now put together two during the successful stretch, including a 27-point, 14-assist, 14-rebound performance during a 118-114, triple-overtime win over Denver last night. The loss of Rajon Rondo has triggered a renaissance by the Celtics captain. “Roles expand. I know what I’m capable of, but when you have a guy like Rondo, not as much is needed from you because you have another guy who can do so many things also,” said Pierce. “So I think with him out the roles (have to) change. I’m gonna be more of a facilitator for this ballclub, and you know it has to come from not only me. It’s got to come from a number of guys. You see other guys being able to step up, we were scoring more. So it’s not only me, its everybody whose roles change.” Some long hours When the Celtics engaged in five overtime games — and seven periods overall — with the Chicago Bulls during the first round of the 2009 playoffs, few probably thought fate would turn that way again. During this seven-game winning streak, the C’s have beaten Miami in double overtime and Denver in triple overtime — and now have pushed games beyond regulation nine times this season, with a 5-4 record to show for the effort. Last night included, four of those games have gone to double overtime or longer. The Celtics’ previous triple-overtime game — a 128-127 playoff loss to the Bulls — came on May 30, 2009. Their previous regular-season triple-overtime game was also a loss, on Jan. 13, 2006, to the 76ers in Philadelphia.