World number four Carlos Alcaraz marched into the US Open last 16 with an impressive straight-set victory over American hope Jenson Brooksby.

Ninth seed Andrey Rublev came through a final-set tie-break against Denis Shapovalov to set up a fourth-round meeting with Britain's Cameron Norrie.

Rublev won 6-4 2-6 6-7 (3-7) 6-4 7-6 (10-7) in a four-hour epic.

Norrie beat Danish teenager Holger Rune in straight sets earlier on Saturday to reach the fourth round at Flushing Meadows for the first time.

Alcaraz, meanwhile, will face either Britain's Dan Evans or Marin Cilic in the last 16 after his ruthless disposal of home favourite Brooksby.

"In the tough moments, break points, I played really aggressively - I was there all the time and I made the most of my opportunities," said Alcaraz.

The 19-year-old Spaniard won the key points in the opening two sets, converting three of six break chances and only dropping serve once.

Brooksby, 21, threatened a fightback by breaking serve twice to go 3-0 up in the third set but that simply spurred Alcaraz on to produce his best tennis of the match.

He reeled off six successive games to progress despite almost literally running his shoes into the ground as he was forced into a mid-game change of footwear.

"It is the third time I have broken my shoes - as you can see I ran a lot to get all the balls so it is normal for me," the third seed joked in his on-court interview.

American Frances Tiafoe, always a crowd favourite at Flushing Meadows, delighted the home fans again by beating 14th seed Diego Schwartzman 7-6 (9-7) 6-4 6-4.

He will now play either 22-time Grand Slam champion Rafael Nadal or Frenchman Richard Gasquet, who meet in the night session on Arthur Ashe.

Italian 26th seed Lorenzo Musetti was knocked out by Belarusian Ilya Ivashka, who won 6-4 3-6 6-2 6-3. Ivashka faces Italian 11th seed Jannik Sinner or American Brandon Nakashima next.

Rublev and Shapovalov steal show on Grandstand

Russia's Rublev, playing under neutral nationality because of the ongoing conflict in Ukraine, and Canada's Shapovalov produced one of the contenders for match of the tournament on the Grandstand court.

There was little hint of the drama to come when the players traded the opening two sets in little over an hour before Shapovalov edged ahead by winning the third-set breaker.

Rublev kept himself in the match by finally converting his fifth set point to level at two sets apiece and looked last-16 bound when he broke 19th seed Shapovalov at 4-4 in the decider.

However, the 23-year-old saved three match points with some blistering groundstrokes before breaking back on the way to a deciding tie-break.

The tie-break was a microcosm of the match as Rublev's accuracy prevailed over Shapovalov's power. The Canadian sent down 23 aces to the Russian's nine across the match and 75 winners to 38 - but also hit 72 unforced errors compared with Rublev's 37.

Rublev took advantage of Shapovalov's mistakes to build up an 8-5 lead and despite the Canadian saving a fourth match point, the fifth proved beyond him as the victor sank to the ground in a mixture of relief and exhaustion before sharing an emotional embrace with his beaten foe as the crowd rewarded both players with a standing ovation.