AUSTIN Its hard to put Connor Zilisch off his game, as the 18-year-old road course prodigy proved once again in winning Saturdays Focused Health 250 NASCAR Xfinity Series race at Circuit of the Americas.

A commitment line violation couldnt do it. Sent to the rear for pitting too when pit road closed suddenly for the races second caution, Zilisch restarted 32nd after the first stage break and drove though the field, taking the lead from Carson Kvapil on Lap 56 of 65 at the 2.4-mile, 17-turn circuit.

Hard contact with the Toyota of Corey Heim couldnt do it. Fighting for position in the final stage, Zilisch slammed into Heim, knocking him off course. The wheel-to-wheel contact damaged the right front fender of Zilischs No. 88 JR Motorsports Chevrolet and caused a serious tire rub under hard braking.

Hot pursuit from Carson Kvapil couldnt do it. After making what proved to be the winning pass, Zilisch had to fend off his teammate until Kvapils right front tire went flat on Lap 60. That gave Zilisch all the breathing room he needed as he nursed his car to the finish line.

Runner-up William Byron trimmed a four-second lead to 1.639 seconds at the finish but couldnt mount a challenge over the closing laps.

As a result, the pole winner had his second Xfinity Series victory, adding to his maiden win in his first start in the series last summer at Watkins Glen.

That was way harder than I wanted it to be, said Zilisch, who scored the much-needed victory after respective finishes of 27th and 34th in the first two races of the season at Daytona and Atlanta. I did not drive a clean race at all I was kind of mentally fogged halfway through that race.

I made way too many mistakes I was glad we were able to fight back.

Byron was driving the No. 17 Hendrick Motorsports Chevrolet that won last years Xfinity race at COTA with Kyle Larson behind the wheel.

My car was just kind of floppy in the short run, and I had to try to take care of it, said Byron, who will defend his win in the NASCAR Cup Series race on Sunday. I just tried to stay with it there in the long run I had fun. It was a good workout.

It was good to get back into the rhythm of things, pushing the car. I think itll help me for (Sunday).

Zilisch is looking forward to Sunday, too. Hell make his NASCAR Cup Series debut in the EchoPark Automotive Grand Prix (3:30 p.m. ET on FOX, PRN and SiriusXM NASCAR Radio).

Its been a fun weekend, but weve got a big race tomorrow, so Im looking forward to that as well, said Zilisch, who will start 14th.

Sam Mayer ran third on Saturday, with Austin Hill, last weeks Atlanta winner coming home fourth. Hill charged from fourth to first after a Lap 46 restart when Zilisch and Kvapil ran wide into Turn 1.

But Hills lead was short-lived. When he over-drove Turn 6a on Lap 52, Kvapil shot past him into the lead, and Zilisch followed into second.

Four laps later, Zilisch had the lead for good, though Kvapil made it a contest until his tire deflated.

Christian Eckes finished fifth. Jesse Love, Taylor Gray, Ross Chastain, William Sawalich and Blaine Perkins completed the top 10.