Worley (2-0) allowed one run and four hits, striking out a career-high seven batters in his fourth start in the majors. Worley is filling in for the injured Joe Blanton.
The NL East-leading Phillies have won 10 of 13.
Jason Marquis (3-1) gave up 10 hits and six earned runs in five-plus innings in his worst start of the season. His ERA rose from 2.62 to 3.66. Marquis was seeking his 100th career win and was trying to go 4-0 for the first time.
Ibanez snapped an 0-for-35 slump with a pair of doubles on Tuesday, and is now 5 for 7 since the skid.
Ibanez gave Philadelphia a 1-0 lead when he connected on the first pitch from Marquis in the fifth. Ibanez hit a high drive deep into the seats in right-center.
The Phillies added two more runs in the inning on Shane Victorino's RBI single and Placido Polanco's sacrifice fly.
Adam LaRoche hit an RBI double to cut Washington's deficit to 3-1 in the sixth, but Philadelphia chased Marquis with four in the sixth.
Danny Espinosa hit a three-run shot off Danys Baez with two outs in the ninth.
Worley has allowed just one run and six hits in 12 innings in his two starts since coming up from Triple-A Lehigh Valley. He already has as many wins as Cliff Lee, one of Philadelphia's four aces.
On a chilly night at the ballpark, a crowd of 44,123 made it 152 straight sellouts in Philadelphia, including postseason play.
Nationals manager Jim Riggleman was ejected in the fourth when he came out after LaRoche was upset with a called third strike. LaRoche dropped his bat at the plate and had a few words for umpire Alfonso Marquez, so Riggleman left the dugout and got the quick ejection.
J.C. Romero pitched a scoreless seventh for the Phillies in his first appearance since going on the disabled list April 19 with a right calf strain.
NOTES: The Nationals said Michael Jacob Allen, the stepson of Davey Johnson and son of Susan Johnson, died Tuesday at 34 from infection and pneumonia in Orlando, Fla. Davey Johnson is the senior adviser to general manager Mike Rizzo. ... Nationals OF Jayson Werth went 1 for 4 against his old team. ... Nats LF Michael Morse was a late scratch because of right knee soreness. Laynce Nix took his place in the lineup. ... Brian Schneider was 1 for 25 off Marquis before hitting a single in the fifth. ... Washington's Matt Stairs singled in the ninth for his 100th career pinch hit, most among active players.