CLEVELAND – David Montgomery's preseason debut Saturday night was a successful one.

After sitting out wins over the Chiefs and Seahawks, the Bears starting running back rushed for 28 yards on nine carries—and had a nifty 24-yard scamper nullified by a penalty—in a 21-20 victory over the Browns at FirstEnergy Stadium.

"I hadn't played in the two previous preseason games, so just to be able to get out and get my feet wet and kind of get back to where I was, it was good for me," Montgomery said.

The 2019 third-round pick from Iowa State showed tantalizing cutback ability on the 24-yard run that was wiped out by a penalty and a 13-yard run to the Browns' 12 that set up the Bears' second touchdown early in the second quarter.

"I love to get in open space and kind of show what I can do," Montgomery said. "I love it. Hopefully we can do that a lot, a bunch this year, so I'm excited."

As Montgomery approached the sideline on his 13-yard run, he squared his shoulders, lowered his head and drove cornerback Martin Emerson Jr. back a couple yards instead of running out of bounds.

"That's just who I am," Montgomery said. "But at the same time, that's the 'HITS' principle that coach Flus (Matt Eberflus) teaches, being able to stay physical and not going out there and playing soft."

Montgomery, who played the first four series, also had one catch for five yards.

"He practiced really well this week, so it's no surprise," Eberflus said of Montgomery's performance. "You play how you practice. He was excited all week to do it, and he performed tonight. We're excited about where he is."

All alone: Tight end Cole Kmet will probably never be more wide open than he was late in the first half when he hauled in a 24-yard touchdown pass from Justin Fields, enabling the Bears to extend their lead to 21-0.

As Fields rolled to his right, Kmet slipped into the right corner of the end zone without a defender within 10 yards of him.

"We ran that play earlier," Kmet said. "Earlier, that hook defender fell off of me and [fullback] Khari [Blasingame] got the ball (for a 6-yard reception). We knew this time that maybe he might bite on Khari, knowing that he got the ball the last time. The safety and the cornerback doubled our post [route] and I came open."

Kmet caught three passes for 36 yards in the game.

Perfect throw: Kmet was the second Bears tight end to catch a TD pass from Fields. The first was veteran Ryan Griffin, who snared a perfectly-thrown 22-yard rope in the left corner of the end zone midway through the first quarter.

Fields squeezed the pass into a tight window, splitting cornerback Herb Miller and safety John Johnson III.

"It was a perfect throw," Griffin said. "It was a three-deep coverage and [it was thrown] between the safety and the corner there in that third. If Justin put any more air under it, it would have been picked. He put it right on a line and right in my stomach and we scored."

Griffin made his preseason debut after sitting out the first two games.

"This was my only preseason action this year," he said, "so I really wanted to show what I could do out here, put some good stuff on film, some violence and show them that I can catch the ball a little bit too."

Making plays: Rookie second-round cornerback Kyler Gordon displayed his instincts and ball skills early in the second quarter, diving to break up a third-down pass intended for tight end David Njoku, forcing the Browns to punt.

"I love making plays, so it was a great feeling to go out there and finally touch the ball," Gordon said. "Hopefully I can get a pick next time."

Gordon was part of a Bears defense that did not allow a touchdown in the first half while forcing three-and-outs on three of Cleveland's first four possessions.

Stepping up: With receivers Byron Pringle, N'Keal Harry, Tajae Sharpe and Velus Jones Jr. all unable to play due to injuries, veteran Dante Pettis took advantage of expanded playing time. The fifth-year pro caught three passes for 37 yards and one touchdown and returned two punts for 17 yards.

"It sucks when people get hurt, but it's football," Pettis said. "I've been hurt; someone else behind me has stepped up. So that's kind of how the game goes."

Pettis' TD came on a 12-yard pass from Fields in the left corner of the end zone, giving the Bears a 14-0 lead early in the second quarter.

"It was a quick post-corner," Pettis said. "The DB was lined up inside of me anyway, so I kind of knew that I had good leverage. I tried to take my time and make sure I wasn't too quick. I turned around and saw the ball in the air."

Pettis again showed his versatility by contributing on offense and special teams.

"The more you can do, coaches love that," he said, "so I'm just glad that I had an opportunity to play both offense and punt return today."

Wire-to-wire: Fifth-year pro Greg Stroman Jr. produced a pair of impact plays. The first came in the second quarter when he stepped in front of receiver Anthony Schwartz and intercepted a Jacoby Brissett pass at the Bears' 38.

"It was a slant," Stroman said. "I just got inside of it and the ball was coming. The play happens quick, just kind of read it and slide in front of him."

Late in the game, Stroman broke up a pass intended for former Bears receiver Javon Wims on fourth-and-6 from the Chicago 15, turning the ball over on downs with just 3:20 remaining in the fourth quarter.

Few players play wire-to-wire in the preseason finale. But after sitting out the first two contests, Stroman was thrilled to be given the opportunity to show what he can do.

"Feels good to just play football," he said. "I missed the first two. I'm blessed to just be able to go out and play football, so I was giving it everything I had."

Sitting out: Linebacker Roquan Smith did not play Saturday night. Appearing on the Fox 32 TV broadcast, general manager Ryan Poles revealed that the veteran linebacker experienced "some tightness" during pregame warmups.

In addition to Smith and the aforementioned four receivers, other Bears who did not suit up were running back Trestan Ebner; center Lucas Patrick; defensive ends Robert Quinn and Mario Edwards Jr.; defensive tackle Angelo Blackson; cornerbacks Jaylon Johnson, Tavon Young, Thomas Graham Jr. and Justin Jones; and safeties Eddie Jackson and Jaquan Brisker.

One-liners: Saturday night's win gave the Bears a 3-0 preseason record. It's their first undefeated preseason since they went 4-0 in 1994 … From halftime of their preseason opener to late in the second quarter Saturday night, the Bears outscored the Chiefs (19-0), Seahawks (27-11) and Browns (21-0) by a combined 67-11 … Cairo Santos missed his only field-goal attempt of the game, hitting the left upright on a 48-yarder midway through the fourth quarter.