GREEN BAY, Wis. — Oh, brother!

Eli, the baby of the Manning quarterback clan, finally has arrived.

And he's taking the New York Giants on yet another road trip — to Glendale, Ariz., site of the Super Bowl.

Manning repeatedly put the Giants in position to win the NFC championship yesterday, and when Lawrence Tynes came through at last with a 47-yard field goal in overtime, New York had itself an improbable 23-20 victory over the Green Bay Packers at frostbitten Lambeau Field.

Now comes Mission Impossible: beating the undefeated New England Patriots in two weeks in a Super Bowl matchup hardly anyone saw coming.

"We haven't been given a shot, but we're here," Manning said. "Right now I'm excited as I can be."

Manning wasn't the only Giant who came through. Tynes had two earlier misses — a 36-yarder at the end of regulation following a bad snap, and a 43-yarder with 6:49 to go — before nailing his long winner 2:35 into OT.

He got a reprieve in overtime after Corey Webster intercepted a struggling Brett Favre — the kind of mistake Manning often has made before his recent turnaround.

"I screwed it up twice," said Tynes, who sprinted straight to the locker room after his decisive kick, leaving his frozen teammates to celebrate outside. "Thank God we got another opportunity."

Manning's arrival comes one year after older brother Peyton won a Super Bowl for the Indianapolis Colts, earning MVP honors to boot. Peyton stayed away yesterday, but father Archie was on hand for the biggest moment of his youngest son's career.

"We knew we could compete with anybody," Manning said. "It's just a matter of getting hot at the right time."

Nobody, not even league MVP Tom Brady, is hotter than Eli.

Just a month ago, Manning's moxie was being questioned as the Giants struggled to clinch a wild-card berth. He responded with the best work of his four-year career, including four touchdown passes in the season finale against the Patriots.

He and the Giants are getting another shot at New England, the first team to go 18-0. The Patriots will be after their fourth Super Bowl title in seven years on Feb. 3, as well as the league's first perfect season since Miami went 17-0 in 1972.

But don't discount New York, which led the Patriots by 12 points in the third quarter before falling 38-35 on Dec. 29.

"Heck, they could win two weeks from now," Favre said. "I wouldn't put it past them."

The Giants (13-6) had a handful of opportunities to put away the Packers (14-4) as Favre struggled with the minus-3 degrees temperatures and wind-chill of minus-24.

Along with Tynes' misses after making two first-half kicks, the Giants fumbled after making their first interception, allowed a long kickoff return after taking a lead, and had some critical penalties that kept Green Bay closer than it probably deserved to be.

Still, the Giants grabbed their first NFC championship in seven years, capping a monthlong surge that reversed a trend of mediocrity built around Manning's inconsistency. He has been a revelation in the playoffs, however, and his calm leadership keyed New York's turnaround.

"It feels good because this is what you work for," Manning said. "We stuck with it, we believed in ourselves and we got to the Super Bowl."

Manning shook off conditions that would make a Siberian husky shiver. He repeatedly put the Giants in position to win in the third-coldest championship game ever — and certainly the most frigid of his young career.

And then he saw Tynes make his first game-winning field goal of the season in the first OT title game in nine years.

"We just came out here and played our hearts out," said Plaxico Burress, who had a career-high 11 catches for 154 yards.

As for Favre, his emotions were clear: "I was disappointed that the last pass I threw was intercepted."

He wound up 19-for-35 for 236 yards and two interceptions. It's now a decade since the career leader in most NFL passing categories has been to the big game.

"For me, I kept thinking how many opportunities are we going to let slip away," he said.

New York, which also won at Tampa and Dallas in the playoffs, was aided greatly by four penalties against the Packers during the Giants' seven-minute, 69-yard march to begin the second half. Brandon Jacobs bolted in from about an inch out after successive offside calls just moments after his third-down fumble was recovered by tight end Kevin Boss. But the biggest miscue was Nick Collins' 15-yard roughing-the-passer penalty on Manning, whose throw was blocked on a third-down play.

Jacobs faked a Lambeau Leap after his score, incensing the hardy souls in the full house of 72,470.

They were stamping their frozen feet in delight seconds later when Tramon Williams, seemingly trapped along the left sideline, cut right and returned the kickoff 49 yards to the New York 39. Then it was the Giants' turn to commit a costly, senseless penalty when Sam Madison negated a third-down stop with a personal foul against Vernand Morency.

Favre immediately pounced with a brilliant play-fake that sprung tight end Donald Lee free in the back of the end zone for a 12-yard TD reception and a 17-13 lead.

With the footing holding on a field heated by pipes underneath, Domenik Hixon got the Giants' next scoring drive started with a 33-yard kickoff runback. Then, Manning kept picking apart the Packers' staple man coverage, a 23-yard diving catch by Amani Toomer setting up rookie Ahmad Bradshaw's 4-yard TD run.

Rookie Mason Crosby's 37-yard field goal tied it 20-20 after a huge break for the Packers. Favre's desperation heave was intercepted by R.W. McQuarters deep in New York territory, but he fumbled when he was hit by Ryan Grant on his return. Tackle Mark Tauscher recovered, giving the Packers another life.