Two No. 1 pick quarterbacks a draft apart, Manning and Smith meet Sunday in the NFC championship game with a shot at the Super Bowl after each has faced immense scrutiny over the years while playing on opposite coasts.
Early on, there were the questions about whether Manning would ever become an elite NFL quarterback like the other big-time QBs in the family, including father, Archie.
"I consider myself in that class," Manning said in August.
Smith, drafted No. 1 from Utah in 2005 one year after Manning was the top pick out of Ole Miss, won't begin to compare his situation out West to what Manning has endured.
"His is a little different. To be Peyton's little brother, No. 1 pick, you go to New York with the Giants, obviously that's a lot of pressure," Smith said. "I don't think anyone has been in the situation he has. Those are pretty unique circumstances. Your older brother is arguably the greatest quarterback ever and a lot of expectations on you and then you go to the big city like New York. I didn't have to face those things."
Smith got booed by his home fans at some point in nearly every game at Candlestick Park in recent seasons before leading a remarkable turnaround this year under first-year NFL coach Jim Harbaugh. He's been benched and belittled by more than one of his coaches along the way.
"I was saying this a few years ago and got laughed at, but Alex was a guy that had about 60 percent of his ability, his potential brought out in him because of all kinds of circumstances," said Trent Dilfer, ESPN analyst and Smith's former teammate. "What he was really relying upon to survive in the NFL was his mental and emotional strength, toughness, giftedness, whatever you want to call it. He is so mentally strong, so resilient, refuses to let the demons affect him negatively. ... I knew once somebody came here and was able to develop him and train him like he started to get trained with Norv (Turner) in 2006 that you would start to see some of the physical stuff come out. I'm just so happy for him because he found a guy in Jim Harbaugh who coached him the way he needed to be coached."
Sunday's game will mark the second time two former No. 1 pick QBs will square off in the conference championship. Vinny Testaverde and John Elway met in the 1998 AFC championship game.
Manning and Smith have their teams on a roll. Each led five fourth-quarter comebacks during the season, then Smith had another in last Saturday's thriller in which he hit Vernon Davis from 14 yards for the game-winning touchdown with 9 seconds left.
That gives Manning some added incentive as he arrives again in the Bay Area.
"This is where you want to be. We always talk about finishing and playing your best football at the end of the season. That's what we're doing now," Manning said. "We're playing great football on both sides of the ball. We have to continue to do that. We're playing smart. We can't turn the ball over."
Manning threw for 330 yards and three touchdowns to stun the defending champion Packers last weekend at Lambeau Field.
"As a freshman, I thought he was the greatest quarterback ever," Willis said. "That was the best season I'd ever had in football. To see the things that he's done, he's won a Super Bowl. That's the biggest accomplishment that we all try to go for, to win that. He's done that. He led his team back to being one game closer to that."
"I always had confidence in Alex. He'll make plays, he will," Davis said. "And since Harbaugh stepped in, he didn't do anything but help Alex, help Alex get better. And to me, Alex is still growing. He still has a lot of room to get better."
Smith became one of five quarterbacks in playoff history to throw three touchdown passes without an interception and run for another, and he helped the 49ers become the first team in the NFL to score two lead-changing touchdowns in the final 3 minutes to win a playoff game, according to STATS LLC.
What a comeback road it's been considering he has played for seven offensive coordinators in as many seasons, dealt with a shoulder injury that sidelined him and faced two head coaches questioning both his talent and toughness.
"You have to have thick skin," said Young, who visited with Smith this week. "The guy has been through hell as far as quarterbacking. He's been through quarterbacking hell where you have a different coordinator, different language. He was trying to describe it like learning French and then learning Spanish and learning Japanese and just learning every weird, new language and having to be held accountable without the support.
"And this year, all of a sudden, he gets all of the support and he feels like: `Geez, I feel like I'm doing less. I feel like it's easier.' But yet, now he's doing remarkable things."
Smith was ready to walk away after last season, a year that began with promise only to deteriorate in a hurry with an 0-5 start. The Niners fired offensive coordinator Jimmy Raye early, wound up 6-10 and fired coach Mike Singletary with one game left. The playoff drought reached eight years.
Even this season, Smith had his share of doubters - even after ex-NFL quarterback Harbaugh came aboard as the new coach ready to guide him.
Smith passed for a career-best 3,144 yards and 17 touchdowns with only five interceptions.
He seems unfazed with that not-so-complimentary "game manager" tag everybody put on him this season. Until his career-defining moments last weekend, Smith was known for doing just enough, nothing flashy.
"Well, he's been doing that all year, the way he's been leading this team, the way he's been playing, it's confidence," defensive tackle Justin Smith said. "It rubs off on everybody. With what he's been through here and the way he's handled himself, it's a good example for all the guys here in how to do it. Hopefully, he's got his game-manager label or whatever that label is off of him. Just put baller on there."