Any given Sunday ... every quarterback has a shot to sit atop the Total QBR leaderboard. While QBs are most often judged by wins and losses or touchdowns and interceptions, we like to rank them every week by the stat that measures their per-play contribution to their team's cause.
An explainer of QBR can be found here, but the main idea is to capture more elements of a quarterback's play than traditional methods consider. QBR includes the value (or lack thereof) of quarterback rushing, sacks, fumbles, relevant penalties, and -- crucially -- the down and distance of every play. QBR works on a 0-to-100 scale, with 50 roughly average and 75 about Pro Bowl-caliber play.
Each Tuesday in this space, we'll highlight the best and worst QBR performances from the NFL weekend and break down what made each quarterback perform at either extreme.
Which quarterbacks were the best and worst of Week 6?
Top three
1. Carson Wentz, Philadelphia Eagles
Total QBR: 95.9
After back-to-back middling weeks in which the Eagles went 0-2, Wentz responded with a career-best 95.9 Total QBR in Week 6 against the Giants.
No matter how you evaluate his effort, he looked great. The most important aspect was avoiding negative plays, however. Wentz was sacked only once and had positive expected points added on 30 of his 42 action plays (71 percent), the highest rate of his career.
Wentz also was an incredible 13-of-14 on third down with nine of those 13 completions going for a first down. Of quarterbacks who attempted at least 14 third-down attempts, none has a completion rate that high since Kyle Orton matched Wentz's 13-for-14 performance in Week 14 of 2014. -- Gargiulo
2. Dak Prescott, Dallas Cowboys
Total QBR: 95.3
Prescott's 95.3 in Week 6 was his highest QBR in a game since a 95.8 back in 2016 -- and the highest QBR the Jaguars have allowed in a game since Colin Kaepernick torched them for a 99.8 (on a much, much smaller number of plays) in 2013.
Prescott had the best rushing performance of his career, going for 82 yards on 11 rushes. His biggest run was a 17-yard touchdown run to put the Cowboys up 10-0 late in the first quarter. He also had a big 28-yard scramble in the third quarter to help set up a field goal.
He also had some big plays on third down to keep the Cowboys' offense moving. In the first half, he hit Michael Gallup for a 27-yard completion on a third-and-9. Looking Cole Beasley's way, Prescott found his trusty slot receiver for a 21-yard completion on a third-and-11, and then completed a pass to Beasley on third-and-7 at the end of the first half for a 9-yard touchdown. -- Gargiulo
3. C.J. Beathard, San Francisco 49ers
Total QBR: 88.9
The second-year quarterback nearly pulled off an upset on Monday night in what was his most efficient game of the season. Beathard was not asked to shoulder as much of the load as he had been in his past two starts since taking over for Jimmy Garoppolo, accumulating only 29 action plays, down from 46 two weeks ago and 67 last week.
Beathard hit on some big plays, leading to his high QBR, including the 67-yard touchdown pass to Marquise Goodwin -- which traveled 42 yards downfield before Goodwin took it the remaining 25 yards -- and an 11-yard scramble on third-and-9 on the 49ers' final drive of the first half that resulted in a field goal.
His late-game interception held him back from being higher on the list, but consider that if it merely fell incomplete, the 49ers would have been left with a fourth-and-3 at the Packers' 46-yard line. Would they have attempted a long field goal? If they had punted, would it have ended up inside the 10 where Green Bay ultimately started the ensuing drive? Or would the 49ers have gone for it? The situation it put Green Bay in was still 90 yards from the end zone with 1:07 left and no timeouts. -- Gargiulo
Just missed: Philip Rivers, Los Angeles Chargers (88.9); Joe Flacco, Baltimore Ravens (86.9)
Bottom three
1. Eli Manning, New York Giants
Total QBR: 3.6
The Giants' offensive line is a dumpster fire, and Manning looks finished. Both of these things can be true, in contrast to the debate that raged on Friday morning. As ESPN writer Bill Barnwell pointed out, Manning was brutal even if you take away all the snaps when he was under pressure.
Though no offense aims to put its QB under pressure, it is the quarterback's responsibility to make the most of what he's given. Manning did not do that when he was under duress on Thursday night.
The upside for the Giants? Big Blue now has a 52 percent chance at landing another top-five pick. -- Walder
2. Marcus Mariota, Tennessee Titans
Total QBR: 14.4
Mariota's eight worst QBR plays on Sunday?
Sack. Sack. Sack. Sack. Sack. Sack. Sack. Sack. In fact, 11 of his 13 worst QBR plays were sacks.
Now, some may quibble with the notion that Mariota ought to be debited for all of those. And certainly, QBR doesn't place all the blame on him. But consider that the average time of those 11 sacks was 4.6 seconds after the snap, according to NFL Next Gen Stats. The average time to pass in the NFL is 2.5 seconds. By 4.6 seconds, the quarterback has to figure out a way to have the football out of his hand. Mariota wasn't entirely responsible for Sunday's drubbing, but he played a big role in it. -- Walder
3. Baker Mayfield, Cleveland Browns
Total QBR: 14.5
Mayfield's QBR has declined every week since he took over for Tyrod Taylor in Week 3. In that relief appearance, he had a week-best 96.1 QBR. But he followed it up with a 53.1, a 41.0 and a 14.5 in Week 6 against the Chargers.
The Chargers sacked him five times. Mayfield's worst sack came midway through the second quarter while trailing by only four when he was dropped on a third-and-6. It pushed the Browns from plausible field goal range at the Chargers' 35-yard line all the way back to the 41. Cleveland elected to punt instead of attempting the long field goal.
Mayfield was also not able to consistently complete throws 10 or more yards downfield. His completion percentage of 23.5 on those passes is a season low, and he hadn't finished at less than 40 percent in any of his previous three games. -- Gargiulo
Just missed: Deshaun Watson, Houston Texans (17.0); Derek Carr, Oakland Raiders (21.6)