DENVER -- Something needed to change. Whatever Ben McAdoo and the New York Giants were doing wasn't working the first five weeks of the season when they had lost every game they played.

McAdoo thought it was best to give up his playcalling duties. He did not call plays Sunday night in Denver for the first time in a regular-season game since he was hired by the Giants in 2014. Instead, offensive coordinator Mike Sullivan called the plays in a stunning 23-10 win against the Broncos.

It was a move that had to be made.

"It's more than just today. I need to do what is best for the team, just like we ask the players and just like we ask the coaches," McAdoo said. "I thought the team and the whole locker room needed me this week. I needed to be at my best for these players and coaches this week."

McAdoo didn't give specifics about the benefits it has for him during the game. Maybe he can be more hands-on in assisting Steve Spagnuolo with the defense? Maybe he can be more involved in special teams or concentrate on game management? These seem like the obvious advantages of not being the full-time playcaller.

It's also possible that the stammering offense just needed a jolt. Sullivan seemed to pull the right strings early. The Giants went 69 yards on 13 plays, using more than seven minutes on their opening drive. He was calling all the right plays, until they stalled in the red zone.

The Giants still moved the ball with relative success throughout the contest against the league's No. 1 defense. They were in Denver territory on five of their 11 drives, even if they only finished with a pedestrian 266 total yards.

Given the success it's a no-brainer for them to stick with Sullivan as the playcaller next week against another tough defense when the Seattle Seahawks come to MetLife Stadium.

"We'll revisit it moving forward but it looks like a pretty good plan," McAdoo said.

Sullivan put together a fairly successful game plan that featured more two-tight-end sets and running plays than usual. The Giants used 12 personnel (two tight ends, two wide receivers and one running back) on 72 percent of their offensive plays against the Broncos, according to Pro Football Focus. The NFL average is 19 percent.

It's in stark comparison to what the Giants were last season and early this season, when they were running three-wide-receiver sets more than any other team in the league.

But this Giants team needed change. McAdoo realized it was necessary and made the decision early in the week. He told Manning, but most of the Giants players didn't know until the game. Guard Justin Pugh and center Brett Jones said they didn't even realize until they returned to the locker room after the game.

They all saw an offense that operated differently, in part because of their altered personnel (no Odell Beckham Jr., Sterling Shepard and Brandon Marshall) and because of their opponent. McAdoo played a part in developing the game plan. Sullivan then executed it by calling 31 runs and 23 passes. That's 57 percent passes and 43 percent runs.

The Giants were 70:30 pass:run with McAdoo calling plays the first five weeks of the season.

It can be argued that McAdoo waited too long to pass along the playcalling duties. The Giants (1-5) were already in a big hole, and their offensive struggles dated to last season. It wasn't as if the change included any major overhaul, either.

Sullivan calls plays at practice and has done it in the preseason. He's hardly an unfamiliar voice in Manning's headset. They have been working together for years.

Sullivan's first crack at being a playcaller in this offense in a regular-season game earned him some praise.

"I thought he did a good job just sticking with the run and knowing it was going to be that game, got a little lead and just staying with it," Manning said. "I know as a coordinator and as a quarterback, you want to throw it. They're playing man-to-man, some zero [coverages]. You want to take a shot. But just with the way things were going and the matchups and the way our defense was going, it was best just to stick with it and play conservative."

It seemed obvious for the Giants to keep running against the Broncos. It was working and they needed to make adjustments to their offense with Roger Lewis, Tavarres King and Travis Rudolph as their top three receivers.

But who is to say McAdoo would've stuck to the run like Sullivan? He hasn't exactly shown extended commitment to the running game throughout his Giants tenure. He also hasn't displayed an ability to operate an explosive offense while being a head coach. The Giants have yet to score 30 points in a game since McAdoo was promoted.

For now it's going to be Sullivan's job to try to end that drought as the playcaller. McAdoo can concentrate on handling his team after a drama-filled few weeks that included disciplining cornerback Eli Apple and suspending Dominique Rodgers-Cromartie. If his team was starting to slip away, he reeled them back in and took some major steps in the right direction on Sunday night.