Just six days earlier, Philly's defense couldn't stop anybody.
The Dallas Cowboys moved the ball at will in a 41-37 victory last Monday.
But this unit was rejuvenated against the Steelers (2-1). Ben Roethlisberger had no time to throw and Willie Parker couldn't find any room to run. Juqua Parker had 2½ sacks as the Eagles banged around Big Ben, eventually knocking him out of the game.
Clinging to a 10-6 lead, the Eagles pinned Pittsburgh at the 6 following a 54-yard punt by Sav Rocca. Three plays later, Roethlisberger was under heavy pressure when he threw the ball away in the end zone for a safety.
On Pittsburgh's next possession, Brian Dawkins made a flying sack, swatting the ball out of Roethlisberger's hand and recovering at the Steelers 18. David Akers kicked a 31-yard field goal to ice it.
Roethlisberger was replaced by Byron Leftwich when the Steelers got the ball with just over 2 minutes left. There was no word on his injury.
Westbrook injured his right ankle on the first play of the second quarter. The All-Pro running back appeared to get hurt while hurdling a teammate on a 2-yard run. He walked to the locker room without help, but didn't return.
Coach Andy Reid said X-rays showed the ankle wasn't broken, but Westbrook will have an MRI on Monday.
One play earlier, McNabb was visibly shaken up after getting sacked. He played the rest of the half and took a hard hit to the chest late in the second quarter. McNabb stayed in the locker room after the half, but returned during Philadelphia's second series in the third quarter.
Backup Kevin Kolb was intercepted by Troy Polamalu on his first pass, which was deflected. The Steelers took over at the Eagles 49, but went nowhere.
McNabb got a nice ovation when he returned to the sideline and he replaced Kolb after the second-year pro completed two straight passes.
McNabb completed his first 15 passes and finished 24-for-35 for 196 yards and one TD. Roethlisberger was 13-of-25 for 131 yards. Both QBs threw their first interceptions of the season.
Parker, who had 243 yards rushing in the first two games, was held to 20 yards on 13 carries.
On the same drive Westbrook left the game, the Eagles went ahead 7-3 on McNabb's 20-yard pass to Correll Buckhalter. McNabb completed a 20-yard pass to Hank Baskett on third-and-15 to the Steelers 46.
Buckhalter caught a short pass, eluded a tackler and hurdled another from the 4 to reach the end zone. McNabb moved ahead of Ron Jaworksi for first on the team's all-time list with 176 TD passes.
On Pittsburgh's ensuing possession, the Eagles sacked Roethlisberger three times and forced a fumble. A 31-yard field goal by Akers made it 10-3.
Bryant McFadden's pick set up Jeff Reed's career-best 53-yard field goal that cut it to 10-6.
Reed had kicked a 37-yarder for a 3-0 lead. It was the first time Pittsburgh was inside the 20 and didn't score a touchdown this season after starting 6-for-6.