Halladay pitched seven shutout innings to lead Philadelphia to a 1-0 victory over the Washington Nationals on Friday night.
It was the Phillies 13th win in the last 17 games and kept them 2½ games behind Atlanta in the NL East.
Halladay (16-8) won his sixth straight while lowering his ERA to 2.16. He allowed eight hits, striking out five and walking three, matching a season high. It was the ninth time this season he hasn't allowed a run and the 25th time in 26 starts he has pitched six or more innings.
"He's having a special season," Phillies manager Charlie Manuel said.
For his part, Halladay said his concentration is on helping the Phillies win and not his own numbers.
"None of that matters," he said. "I'm looking at trying to win a division. It's a nice feeling to put all of my [statistics] aside and worry about the bigger picture."
"We pulled it out and were able to get it done," Ibanez said. "We pitched well and got hits when we needed it."
Washington had its chances against Halladay, who worked out of jams in the first, third, fourth and seventh innings. In the first, a double and a pair of walks loaded the bases before Roger Bernadina grounded into a double play.
"I made some pitches when I needed to and had a little luck on my side, too," Halladay said. "It definitely feels good when you can get out of it."
After getting out of one-out, two-on situations in the third and fourth, a single by Ian Desmond and a walk to Adam Dunn put runners on first and second with one out in the seventh. But Halladay escaped when Ryan Zimmerman lined into a double play.
Zimmerman hit the ball hard to left field and Desmond was attempting to steal third on the play, but after a good throw by Ibanez was tagged out by Chase Utley sliding back to second.
Nationals manager Jim Riggleman wasn't upset with Desmond's decision on the play.
"He was running on his own. It was a good play and he had the base stolen," he said. "[Zimmerman] smoked it but it was right at Ibanez."
Marquis had his best start of the season, going five innings and allowing one run on four hits. It was the third start for the right-hander since having elbow surgery May 14.
"I was getting tired of embarrassing myself out there," Marquis said. "It was a step in the right direction."
Said Riggleman, "I thought he did a good job and got ground balls for the most part. I'm very pleased with how he pitched."
The only run Marquis allowed came on a play that could have been an out. With Utley and Jayson Werth on base, Ruiz scorched a ball down the first-base line that glanced off Dunn's glove and into right field.
- Halladay balked in the first inning, his first since April 19, 2005. With his fourth-inning steal, Philadelphia's Jimmy Rollins has stolen 30 consecutive bases without being caught. Washington's Ivan Rodriguez was 1 for 3 off Halladay and is now 14 for 35 (.400) lifetime against the Phillies right-hander.