Austin Hill ran down rookie pole winner Chandler Smith from three seconds back, passed him as the cars approached the white flag and held on to win Saturday's Alsco Uniforms 300 NASCAR Xfinity Series race at Las Vegas Motor Speedway.

The victory was the second of the year for Hill, who won the season opener at Daytona International Speedway. The driver of the No. 21 Richard Childress Racing Chevrolet won for the first time at Las Vegas and for the fourth time in his career.

Smith's car tightened up in the closing laps, allowing both Hill and Justin Allgaier to pass him on the final two circuits. Hill finished .268 seconds ahead of Allgaier, who was closing on the final lap but ran out of time.

Kyle Busch ran fourth in his first Xfinity Series start of the season and lost his chance to complete a Las Vegas triple. Busch won Friday night's CRAFTSMAN Truck Series race at LVMS and will compete in Sunday's Pennzoil 400 Presented by Jiffy Lube NASCAR Cup Series event (3:30 p.m. ET on FOX, PRN and SiriusXM NASCAR Radio).

"When the 16 (Smith) got by me (after a restart on Lap 98), I got really, really loose off of (Turn) 3," said Hill, who led 19 laps and won Stage 2. "Almost wrecked it, saved it. The 16 got really far out. I just knew I had to not abuse the tires and try to methodically just work my way through traffic. The track was really tough today. Had a really thin line between (Turns) 3 and 4. If you missed it by—it seemed like a half of an inch—you paid for it through the whole lap.

"That's just really what I stuck to all race long, was just trying to be disciplined through 3 and 4… I saw the 16 struggling in traffic and my spotter Derek (Kneeland) was like, ‘Come on, baby. You can get it!' I saw him get tight off of (Turn) 4 there, and I knew I painted the line perfectly. I knew if I could clear him down the frontstretch, I felt like once we had clean air, we could hold him off."

In a green flag run to the finish that lasted 103 laps, Smith took the lead from Busch on Lap 102 of 200, regained it on Lap 146 after a cycle of pit stops and held it until Hill powered to the front on Lap 199.

"I just got a little tight there at the very end," said Smith, who led 118 laps. "It is what it is. That's a tough pill to swallow. There are some things I could have done inside before we started building tight. Getting by (lapped traffic)—we needed to have a bigger bumper.

"All in all, I can't be too disappointed. It's my sixth (Xfinity) start, third start with Kaulig Racing. We had a really fast Quick Tie Products Camaro, and I just really appreciate (owner) Matt Kaulig, (team president) Chris Rice, everybody at Kaulig Racing for bringing me on board, believing in me. We're going to win a few races this year, for sure."

John Hunter Nemechek won the first stage but lost track position when he had to pit on Lap 74 because of a loose wheel and never got back in contention for the win. Nemechek, who led 45 laps, finished sixth behind Hill, Allgaier, Smith, Busch and Josh Berry.

"Probably one of the fastest cars—just didn't execute," Nemechek said. "It's frustrating, but to come home sixth after a loose wheel, going to the back and driving back up through. Then pitting and going to the back. Just shows the speed, and we'll have to go to Phoenix (next Saturday) and put it on them."

Sam Mayer, Riley Herbst, Sheldon Creed and Daniel Hemric completed the top 10.