BUFFALO, N.Y. — Brian Boucher stopped 35 shots as the Flyers new starting goalie in helping Philadelphia grab a first-round playoff series lead with a 4-2 win over the Buffalo Sabres on Monday night.Danny Briere and Nikolay Zherdev keyed the victory by scoring second-period goals as Philadelphia bounced back with two straight wins after a 1-0 series-opening loss Thursday.