Philadelphia (8-4-7) completed its recent three-match road trip unbeaten (1-0-2), extending its unbeaten streak to five matches (2-0-3) and overtaking New York for first place in the Eastern Conference with two matches in hand.
New England (3-9-7), which extended its winless streak to nine (0-6-3), hasn't won since May 14. The Revolution have scored just seven goals during their winless streak and have scored one goal or less in 16 matches.
Ruiz, the 31-year old MLS veteran, netted his team-leading sixth goal in the 11th minute, while Valdes, a defender, tallied his first MLS career goal in the 24th - both goals coming courtesy of some slipshod New England defense.
Worsening matters for New England was the red-card ejection of midfielder Benny Feilhaber in the 65th minute for a flagrant hard tackle on Ruiz. Philadelphia's Sheanon Williams scored the Union's third goal in the 93rd minute.
Philadelphia, in just its second season of MLS play, not only won its Eastern Conference-best eighth match of the season, but is now 5-0-2 against conference rivals.
Ruiz, who dominated against the Revolution during his tenure with the Los Angeles Galaxy, finished off a well-constructed set of passes. Justin Mapp sent the ball to the far left side where Keon Daniel headed it toward the net. Ruiz charged on the ball unmolested, sticking his foot out for the go-ahead goal.
Then on a free kick taken by Kyle Nakazawa, Union striker Sebastien LeToux got his head onto the ball, sending it toward the goal mouth where Valdes beat the Revolution defense, sticking his right foot out to tuck the ball into the back of the net.
New England did not have a shot on goal at Philadelphia goalie Fardy Mondragon, who secured his seventh shutout of the season. Other than four corner kicks, two in each half, the Revolution's lone threat came off a Darrius Barnes header over the crossbar after a Chris Tierney corner kick in the 85th minute.
(Copyright 2011 Philadelphia Union. Reprinted by permission)