Silva surrendered a walk-off home run by Wil Cordero leading off the bottom of the ninth as the Montreal Expos posted a 3-2 victory over the Philadelphia Phillies.
Entering the game in relief of starter Brandon Duckworth with runners on second and third and none out in the seventh, Cormier escaped the jam by getting two groundouts around a strikeout.
After getting slugger Vladimir Guerrero to ground into an inning-ending double play in the eighth, Silva (3-1) served up Cordero's fourth homer of the season to start the ninth. The blast was the fifth game-winner of the season for the Expos, who won for the fourth time in five games.
Benefiting from Cordero's heroics was Luis Ayala (5-1), who struck out three in two hitless innings of relief.
Montreal starter Tomo Ohka was strong, allowing two runs and four hits in seven innings. The Japanese righthander struck out seven and retired 15 of the last 16 batters he faced.
Phillies starter Brandon Duckworth pitches six strong innings as well, allowing six hits and walking just one while striking out four.
The game was played in front of a surprising large crowd of 33,236 at Olympic Stadium. With the Braves pounding the Mets 10-4 Saturday, the Phillies are now six games behind Atlanta while the Expos remain two games back.
The series wraps up Sunday with Brett Myers (4-3, 2.59) facing Javier Vazquez (4-2, 3.32).