CHICAGO (AP) — James Cook has come a long way since training camp. All the way to helping the Buffalo Bills roll to a big road win on a frigid Saturday in December.

Cook rushed for a career-high 99 yards and scored his third NFL touchdown during Buffalo’s 35-13 victory over the Chicago Bears. Cook and Devin Singletary led the way as the Bills gained a season-high 254 yards rushing while clinching the AFC East title.

The 23-year-old Cook, the younger brother of Minnesota Vikings running back Dalvin Cook, was selected by Buffalo in the second round of this year’s NFL draft out of Georgia. James Cook had 728 yards rushing and seven touchdowns during his final season with the Bulldogs, helping the school win the national championship.

He got off to a slow start with Buffalo (12-3), totaling 19 carries for 97 yards and a TD in the team’s first six games. But he has been a key performer for the Bills during their six-game win streak, carrying the ball 47 times for 293 yards and scoring twice, including a 4-yard TD reception during last weekend’s 32-29 win over Miami.

“It’s time to roll now,” Cook said. “So you know each and every week I just keep getting better. I just keep practicing harder. Just keep working harder, and good things are going to come to light on game day.”

Cook even outgained his brother on Saturday. Dalvin Cook had 64 yards on 14 carries during Minnesota’s 27-24 victory over the New York Giants. James Cook said he talks to his brother every day, but he had no interest in talking any trash after outperforming him this weekend.

“Nah, at least he had a good game and they got the ‘W,’” James said. “So I ain’t going to mess with him.”

Cook said his brother has been a valuable resource for him as he transitions to the NFL.

“He just tells me, ‘Just keep going, each and every week,’ and that’s what I’ve been doing,” he said.

Buffalo trailed 10-6 at halftime, but Cook helped his team pull away in the second half. He had a 27-yard run with 7:57 left in the third quarter, putting a nice move on Bears defensive back DeAndre Houston-Carson on his way to the end zone and a 21-10 Bills lead.

It was Cook’s first rushing TD since a 24-yarder during a 38-3 victory over Pittsburgh on Oct. 9.

“He’s progressed a lot. He’s learned a lot, obviously,” Buffalo quarterback Josh Allen said. “The speed of the game, it seems like it’s becoming more natural for him now. He’s understanding our concepts and what we’re asking for him.

“To have a little bit of a change-of-pace back that can hit a hole and really go, it’s exciting.”

Cook had 11 carries, and Singletary finished with 106 yards on 12 attempts. Buffalo’s 254 yards on the ground was the team’s best total since it had 272 during a 34-31 loss to Miami on Dec. 24, 2016.

Singletary said they tried to get Cook to 100 yards as well, but it didn’t quite work out. He said he thinks he was more upset about Cook coming up 1 yard short than Cook himself.

“He keeps getting better and better each week,” Singletary said, “and that’s what it’s about.”