Defending champion Carlos Alcaraz secured a stress-free win over Lloyd Harris of South Africa ©Getty Images

Seeded starts turned their fortunes around on Thursday at the US Open with Carlos Alcaraz of Spain and Aryna Sabalenka of Belarus among the winners.

Defending champion Alcaraz secured a stress-free win over Lloyd Harris of South Africa in the second round and is set to face Daniel Evans of Britain next.

The 2023 Wimbledon champion took the first two sets 6-3 and 6-1 before a minor hiccup in the third.

Harris broke Alcaraz in third set but was not able to maintain the momentum, eventually bowing out 6-7.

"I think we [played] great points," Alcaraz said.

"That’s what we are looking for in every match - to make the people enjoy watching tennis... and I think we did it pretty well today."

Second see Sabalenka took only 74 minutes to knock out Jodie Burrage of Britain, ranked 96 in the world, 6-3, 6-2.

Sabalenka is also vying for the world number one spot in the United States.

If she and Iga Świątek of Poland maintain their winning streaks, the duo remain on course to face each other on September 9.

Defending champion Świątek will have to give up her position if she loses before that.

"I didn't lose my focus today, not for a minute," said Sablenka, after her win.

"I'm super happy with my level today."

There were also wins for Grigor Dimitrov of Bulgaria and the home duo of Madison Keys and Jessica Pegula.

Up against Romanian Patricia Maria Tig, third seed Pegula wasted no time in securing a 6-3, 6-1 victory.

There was disappointment again for former world number one Andy Murray of Britain, who went down to Dimitrov.

The Bulgarian despatched the two-time Olympic singles champion 6-3, 6-4, 6-1 while Keys overpowered Yanina Wickmayer of Belgium 6-1, 6-2.

Ukrainian Elina Svitolina, a semi-finalist at the Wimbledon this year, dug deep to win 5-7, 6-4, 6-4 against Anastasia Pavlyuchenkova of Russia.

Daniil Medvedev and Russian compatriot Daria Kasatkina also secured their palaces in the next round after respective victories over Christopher O'Connell and Sofia Kenin.

Medvedev wrapped the game with a 6-2, 6-2, 6-7, 6-2 win over Australian O'Connell while Kasatkina defeated American Kenin 2-6, 6-4, 6-4.