If Sunday’s upcoming Cowboys-Patriots matchup feels like a more monumental game than normal, that’s because it is, with both squads trying to maintain their spots in the postseason chase. It’s the dangerous and streaky Dallas offense against the stifling and surprising New England defense. It’s rising star Dak Prescott’s chance to outgun the veteran Tom Brady and perhaps even signal a changing of the guard of sorts among the league’s quarterbacks. It’s one coach who’s still trying to cement a reputation as a brilliant football mind and motivator matching wits with the unparalleled genius on the opposite sideline. It’s the sport’s two marquee franchises in a regular season showdown that will be a ratings bonanza and spur plenty of wouldn’t-this-be-a-great-Super-Bowl talk among even casual fans.

Most players tend to stay on an even keel when looking ahead to their opponents, being careful not to undersell or overhype any team on the schedule. But the fact is, any-given-Sundays aside, some games are just bigger. Cowboys tight end Jason Witten has been in quite a few over his 16 seasons. And he says the Week 12 clash with the Patriots is a measuring-stick kind of game.

“Yeah, I think it is,” Witten said, per Michael Gehlken of the Dallas Morning News. “There are defining games that happen. You look at last year’s season… and you beat a good New Orleans team. This is one of those games. There’s still a lot of games out there, so I don’t think it’s make-or-break. But at the same time, to be able to go on the road and play against Tom Brady and Bill Belichick and their team, they’re 9-1 like they are. A great opportunity for us.”

While Dallas has overcome slow starts in several of their six wins this season, early errors have also dug deep holes in all four of their losses. Witten knows that the Cowboys can not afford to similarly waste the first quarter in Foxborough against this particular Patriots unit.

“They’re going to pounce on any mistake you make,” Witten said. “They’re prepared. They’re fundamentally sound. Their in-game adjustments are just at a higher level than anybody else in the league. done it at that level for so long. And specifically as an offense going him, I think his defense right now, when I watch them on tape, if it’s not the best defense he’s ever had, it’s got to be up there in the top. It’s a big challenge for us. So much respect for him. Greatest coach to ever coach in the NFL.”

A slow start is tough to overcome against a Belichick team. But turnovers are downright fatal. As NFL.com’s Nick Shook points out, “New England owns a plus-18 turnover differential through 11 weeks, a mark that’s twice as good as the next nearest teams (Green Bay and Pittsburgh are tied at plus-nine). The Cowboys, meanwhile, own a minus-one differential.”

A stray ball from an overly-greedy Prescott (like his Week 3 interception versus Miami) or Ezekiel Elliott putting one on the turf (as he did on the second play of the game in Detroit) could prove to be catastrophic if it happens against an elite opponent like New England; the Patriots have scored six touchdowns on defense and special teams thus far this season.

Witten and the Cowboys know they may well have to play a mistake-free game to notch a season-defining victory over the reigning Super Bowl champions.

“Our guys are up for the challenge,” Witten promised. “We’ve got a lot of healthy respect for them, but just like any other week, you’ve got to prepare and know that you’re going to have to go play your best football.”