JOLIET, Ill. -- Once Kyle Larson got to the top of the track, it was all over.
Larson used the high line Saturday at Chicagoland Speedway to pass Kevin Harvick and drive away to a dominant victory in the NASCAR Xfinity Series.
"You can look at any track where you can run inches off the wall, and I'll be faster than anybody," Larson said. "Once the lap times dropped off enough around the bottom, I could move up there and go really fast."
Riding as high as he could go on the bumpy 1.5-mile oval, Larson passed Harvick with about 60 laps remaining in the 300-mile race. Brandon Jones moved into the top spot when he stayed on the track while the leaders went in for a pit stop, but the caution he needed never materialized, and Larson pulled away when Jones finally went into pit road on a really hot day all over the Midwest.
Larson also won the pole, but the NASCAR Cup Series regular was sent to the back of the field because of an unapproved tire change after qualifying. It was his second win in three starts on the Xfinity Series this season, joining his victory in March at Las Vegas.
Harvick finished second, and Cole Custer was third after also starting at the back of the field due to a tire issue. It was the fifth consecutive top-five finish for Custer, who moved into the lead in the series standings by three points over Daniel Hemric.
"We probably were the best car out there. I think Kyle Larson's probably just the best driver at Chicago," Custer said. "It was a little bit hard to catch him once he started running the top."
Daniel Suarez and Hemric rounded out the top five. Elliott Sadler was sixth and dropped into third in the series after beginning the weekend on top of the standings.
The temperature was in the 90s for most of the day, and it soared well into triple digits inside the cars. Ice bags were almost as popular as new tires at each pit stop. Harvick asked his crew for a smaller, sandwich-sized bag when he was unable to fit a large bag in his suit, and he splashed cold water on his face at one point.
"Water and ice and a towel down here at the start/finish line," Larson requested after his 10th career Xfinity victory.
Chase Elliott pulled himself halfway out of his car and sat in the window with his head resting on the roof for a short while. He then walked to an ambulance and went to the infield care center for fluids.
"It was a rough one, for sure," he said. "One of the hotter days I can remember."
The 25-year-old Larson felt his No. 42 ENEOS Chevrolet was in bad shape after practice on Friday, and he praised his team for its extensive work. He moved in front for the first time about 70 laps into the 200-lap race.
Crew chief Mike Shiplett said they used one of the practice sessions for testing, and it didn't work out how they planned.
"We basically just put the car back to our normal package that we run on mile-and-a-halfs, on these low-grip tracks that he runs up against the wall," he said.
That worked out quite well for Larson & Co.
Tyler Reddick started in front after Larson's tire problem and then won the first stage. But he had a slow pit stop and was penalized for speeding into pit road before he was knocked out of contention by a wreck.
Justin Allgaier, an Illinois native who won the Chicagoland Xfinity Series race in September, finished seventh. He was trying for his second straight victory after winning June 17 at Iowa.