What was encouraging is what he didn't see: a replay on the giant videoboard that hangs above the field at Cowboys Stadium, where the Giants still never have lost following a wild 29-24 victory Sunday.
Officials reviewed and overturned Dez Bryant's apparent 37-yard touchdown catch, ruling his hand hit out of bounds, and the Cowboys couldn't get into the end zone after the overturned reception.
"I couldn't quite believe they were able to hit a touchdown in that situation. I kind of kept looking for the replay," Manning said. "You know the game was not going to be over until that clock hit zero."
This was the 20th time in Manning's career that the Giants rallied in the fourth quarter to win. And this comeback came after New York blew an early 23-0 lead.
"It speaks about our resiliency. We know how to win these games," receiver Victor Cruz said. "We've been in a bunch of them."
After their sixth win in seven games since a season-opening home loss to Dallas, the Giants (6-2) hurriedly cleared out of Cowboys Stadium trying to get home as quickly as possible with Hurricane Sandy bearing down on the East Coast.
The Giants are 4-0 in Arlington since Jerry Jones' football palace opened in 2009 with a New York victory.
"I'm very disappointed right now," Jones said. "I thought after all that, our defense played well enough, our offense kept going and I thought we were going to get a chance to pull one out."
Coupled with Sunday losses by Philadelphia (3-4) and Washington (3-5), the Giants strengthened their hold on the NFC East lead halfway through their schedule.
New York led 23-0 just 2 minutes into the second quarter when defensive end Jason Pierre-Paul returned an interception 28 yards for a touchdown. That was the third of four interceptions thrown by Tony Romo, and Dallas (3-4) finished with six turnovers.
But the Giants didn't score again until Lawrence Tynes made a 43-yard field goal with 10:20 left for a 26-24 lead. He kicked a 37-yarder with 3 1/2 minutes remaining in the fourth for his fifth of the game.
Stevie Brown set up Tynes' last field goal with a fumble recovery and also had two interceptions.
"We have good leadership, good people," Giants coach Tom Coughlin said. "They're fighters in that locker room. ... Sometimes it comes out differently than it was designed."
Dallas got to the Giants 19 on one of its last drives. On fourth-and-1 with 1:03 left, Romo scrambled and was picked off by Brown.
After New York failed to get a first down on three running plays and Dallas used all three of its timeouts, the Cowboys got the ball back with 44 seconds left at the 30. They got to the Giants 37 before Bryant's catch between two defenders in the back of the end zone was overturned.
"We scratched and scraped," Giants defensive lineman Chris Canty said. "At the end, we still had to have a little luck to pull that one out."
Manning completed 15-of-29 passes for 192 yards with an interception.
Romo threw for a career-high 437 yards while completing 36-of-62 passes. Jason Witten broke his own Cowboys team record with 18 catches, which resulted in 167 yards. They were the most catches by a tight end in NFL history, according to Elias Sports Bureau, and were tied for fifth-most overall, according to ESPN Stats & Information.
Miles Austin had nine catches for 133 yards and Bryant had five catches for 110 yards.
The Giants led 13-0 in the first quarter after Romo's first two interceptions.
Brown, who has five interceptions in six games, stepped in front of Bryant and had a 37-yard return to set up Tynes' 37-yard kick that made it 6-0. Three plays later, Corey Webster's 37-yard interception return led to Andre Brown's 1-yard TD.
Michael Coe recovered at the Dallas 15 when Bryant fumbled after fielding a punt over his head, setting up a 26-yard field goal.
Three plays later, Pierre-Paul broke off a block and jumped to grab the ball. He punctuated his first-ever pick and touchdown by dunking the ball over the crossbar.
Things were so bad then that Jones was booed when he came on the videoboard during a public service announcement about breast cancer awareness. On another unrelated video during that same timeout, coach Jason Garrett got the same treatment when his image appeared on the screen.
"I've been to boo school. Seriously," Jones said. "I'm sure the fans had the same feeling I did. I was frustrated, mad. I knew that we had dug ourselves a hole that was going to take a super effort to get out of. But I understand the frustration. I do."
Dallas scored the last 10 points of the half, then added two more touchdowns in the third quarter to go ahead. Romo faked a handoff and rolled right for a 1-yard score on fourth down, ending the play with an emphatic spike.
After the Giants went three-and-out, the Cowboys drove to the 1 again. Romo faked another handoff and started rolling right, when he then shuffled the ball ahead to John Phillips for a 1-yard pass that put Dallas up 24-23.
None of that mattered after the closing sequence.
"Just tough when you think you've won the game," Romo said. "It switches as that moment. You put a lot into it, obviously. We put a week's worth (of emotion) in that one game.
The only Cowboys with more passing yards in a game are Don Meredith (460 in November 1963) and Troy Aikman (455 in November 1998). ... The only other time Dallas had three 100-yard receivers was Nov. 10, 1963, at San Francisco. ... Tynes is now the second-leading scorer in Giants history. His 17 points Sunday pushed his career total to 535 (113 field goals, 196 extra points). He passed Brad Daluiso's 526 points. The career leader is Pete Gogolak's 646.
Information from The Associated Press was used in this report.