ORCHARD PARK, N.Y. – Making his highly-anticipated NFL preseason debut, Bears rookie quarterback Caleb Williams excelled while playing the first two series in Saturday's 33-6 win over the Bills.

Displaying accuracy and mobility, Williams completed 4 of 7 passes for 95 yards with a 101.8 passer rating and had one rush for 13 yards. The No. 1 pick in the draft engineered 58- and 84-yard drives that resulted in Cairo Santos field goals of 31 and 30 yards, staking the Bears to an early 6-0 lead.

"It's good for him," said coach Matt Eberflus. "It's the fruits of his labor. He's been working his tail off for 15 practices and then even before that all through the summer. So it's good to be able to say, 'Hey, all this drill work, all the things I've been doing, it's paying off and I can see improvements.'

"We're going to look at this tape and look back and say, 'What can I learn from this?' There's a lot of things we can learn from this process in getting these reps as he does in practice when he's going against the one defense."

Williams sustained the game-opening possession by rifling a 12-yard completion to receiver DJ Moore on third-and-12, then followed with a short screen pass to running back D'Andre Swift, who raced 42 yards to the Bills' 18.

Eberflus cited the screen play as another example of Williams' "ability to get the ball away really fast when pressure arrives."

"That happens sometimes on those screens," said the Bears coach. "I thought he did a really nice job of getting the ball to [Swift] cleanly and Swift is a guy that's dynamic and really has got a lot of good speed."

The Bears defense forced a three-and-out on Buffalo's first possession, as defensive linemen Dominique Robinson and DeMarcus Walker teamed up to drop running back James Cook for a two-yard loss on third-and-2.

Taking over at their own 3, Williams twice rolled to his right and completed passes of 15 yards to Moore and 26 yards to tight end Cole Kmet. Williams then sustained the drive by scrambling for 13 yards on third-and-nine from the Bills' 32.

The Bears starting offensive line of left tackle Braxton Jones, left guard Teven Jenkins, center Coleman Shelton, right guard Matt Pryor and right tackle Darnell Wright provided excellent protection for Williams.

Replacing Williams to begin the second quarter, backup quarterback Tyson Bagent completed 5 of 8 passes for 47 yards with a 78.6 passer rating before yielding to Brett Rypien late in the third period.

On back-to-back possessions late in the first half, the Bears recorded third-down sacks of Bills backup quarterback Mitchell Trubisky. Defensive linemen Austin Booker and Daniel Hardy split the first one to force a punt and defensive tackle Zacch Pickens recorded the second on the final play of the half.

Auditioning at running back, Velus Jones Jr. rushed for 16 yards on four carries on the Bears' first possession of the second half, capped by a 4-yard TD run that widened the margin to 13-3 with 7:46 left in the third quarter. Jones finished the game rushing for 34 yards on six attempts.

"I thought it was positive," Eberflus said. "He did a nice job of really getting north. He's got really good lean mass and he's a physical player and you could see him really deaden the tackles to fall forward for those positive yards."

Jones said he was more than willing to move from receiver to running back, a switch that took place to begin the practice week.

"God blessed me with speed, size and physicality, so why not?" Jones said. "Anything to help this team out and increase value."

The Bills cut the gap to 13-6 on Bass' 49-yard field goal late in the period after defensive end Daniel Hardy sacked quarterback Shane Buechele for a 6-yard loss.

Early in the fourth quarter, Micah Baskerville produced the play of the day by the Bears defense. Stepping in front of running back Frank Gore Jr., the first-year linebacker intercepted a Buechele pass and returned it 53 yards for a touchdown. Santos missed the extra point, but the Bears led 19-6.

"I saw the quarterback go through his reads," Baskerville said. "I just went ahead and took my guy, and he threw it to him."

Asked what he was thinking during his return, Baskerville said: "Don't get caught by the QB? That's it."

Booker added two more sacks of Buechele on back-to-back plays in the fourth quarter, increasing his total to 2.5 on the day.

"It was a great feeling, a rush of energy and I can't wait to do it again," Booker said. "I've just got to watch the film to see how [I] can improve. There's always stuff I could have done better. I probably could have had two more sacks."

Hardy also generated 2.5 sacks for a Bears defense that recorded eight sacks and did not allow a touchdown in the game.

Rookie running back Ian Wheeler followed with TD runs of 7- and 8-yards on consecutive possessions with 6:03 and 2:24 remaining to widen the margin to 33-6.

"It's something I've been working towards for a while," Wheeler said. "Unfortunately, I didn't get to play in the last game, so my teammates helped me get into the end zone twice and that's [something] I could be happy about."