Peyton and Eli's father Archie would have had contrasting emotions last weekend.
Mixed time for Mannings
What is it like to be Archie Manning? To find out, slip on his shoes and walk a kilometre in them.
You sired Peyton and Eli, the most acclaimed contemporary male siblings in American sports. These two shiny apples fell so close to the tree that they landed alongside the trunk.
Like you once did, they dabble in the exclusive field of professional quarterback. Many a dad lives vicariously through his son. You are afforded double the pleasure - and occasional pain.
Unlike yours did, their teams usually win. Your career record as a starter was 35-101-3 - barely one victory for every four tries - mostly with those lovably losing New Orleans Saints of yore.
Peyton is 123-63 with the Indianapolis Colts, a remarkable pace of almost two wins for each defeat. The New York Giants' Eli is 60-43, success coming at nearly a 60 percent clip.
Both have Super Bowl rings to pawn if times get tough.
The Saints' failure to manage a single break-even season under your watch was not your fault, and you were voted twice to the Pro Bowl, partly as a lifetime achievement award for continuous effort and dignity.
Peyton, in his 13th season, has been to the Pro Bowl since his third year in the league. He sent his regrets last January, having been engrossed in Super Bowl preparations.
Sure enough, a Manning made it to Hawaii with Eli's first all-star gig.
When Sports Illustrated magazine asked players who among them is the smartest, 62 per cent responded with Peyton.
The poll's runner-up - Drew Brees, at 8 per cent - finished so far back in the picture that he was blurry.
OK, Eli did not warrant a single vote, but he still snags more television ads than about every player but his big brother.
Peyton sells enough products on-air to fill a warehouse, landing so many commercials that viewers have compiled lists of their favorites.
So there you are, the Dream Dad, flitting each weekend to one son's game or the other, envisioning Manning versus Manning in Super Bowl XLV. Then turbulence shakes you from your reverie.
The Colts barrel down the Super Bowl express lane until losing three straight, during which Peyton serves up 11 interceptions. Indianapolis fade to 6-6 and, their roster ravaged by injury, are suddenly on the play-off fringe. "What's wrong with Peyton Manning?" The question was posed, by Google's count, 16,700 times in cyberspace.
The Giants, closing in on a 10-4 record and the play-offs, squander a 31-10 fourth-quarter lead in an unfathomable crash-and-burn, won by Philadelphia 38-31 without even needing overtime.
The next Sunday, Green Bay gut the Giants 45-17 as Eli dishes four interceptions, bumping his total to a league-leading 24.
New Yorkers - not enamoured of strong, silent types - assail Eli for an alleged lack of vocal leadership.
Aware that the Manning name carries the burden of high expectations, you are anxious to see how your flesh-and-blood deals with adversity. Their reaction makes you a proud papa.
At the height of his slump, Peyton says, "It really all falls on my shoulders. I have to play better. I've got to make better decisions and better reads."
A widely circulated YouTube video (headlined "Eli Manning post game press conference after Choke") shows little brother waiting in an empty room for the media following the giveaway at Green Bay.
Eli could have ducked out, but he waits for the harsh questions surely to come. "If you have interceptions," he says, "it's my fault, and we had four today."
Come the final Sunday of the season, both the Colts and the Giants are still battling to make the playoffs.
Peyton's Colts can claim the AFC South with a win at home over Tennessee, or a loss by Jacksonville against Houston.
Eli's Giants need a win at Washington plus a Green Bay loss.
Kicking off simultaneously, the two games are taut throughout. Colts fans suffer. Giants fans suffer. Your suffering is the sum of theirs, and then some.
The Colts, tied, cough up a late fumble, setting up a likely Titans field goal. But wait - Jacksonville are losing to Houston.
Eli's 92-yard touchdown toss supplements the Giants' stout defence for a late three-point lead. But wait - Green Bay have pulled ahead of Chicago.
The Colts win in overtime as Peyton sets an NFL one-season record for completions.
The Giants win as Eli gets picked off once, on a deflection - but the Packers win, too.
The Colts finish 10-6. They are in the play-offs.
The Giants finish 10-6. They are not.
The next day, you need a break from walking in Archie's shoes, but your parenting skills are required.
Not to console Eli, but to help ease his passage into a new stage of life.
It is his 30th birthday.