Aryna Sabalenka began her US Open title defence with a 6-2 6-4 win over Colombia's Camila Osorio on Monday, making a confident start to her quest for a third consecutive title at the year's final major.

The world number one, who is aiming for a rare "three-peat" at Flushing Meadows, sealed the match in 87 minutes on Arthur Ashe Stadium. She fired off 32 winners to set up a meeting with Russian qualifier Polina Iatcenko in the second round.

Sabalenka, who would join Serena Williams and Chris Evert as the only women to win three straight US Opens in the professional era, said she was happy with her level of play.

"I'm super happy with the level I played," Sabalenka said. "I feel like this is one of my favourite stadiums, I really experienced the best emotions here on this stadium."

Sabalenka has been trying to turn around a difficult second half of the season, having failed to reach a final since winning at Indian Wells and the Miami Open to complete the Sunshine Double in March. She has lost seven of her 24 matches since then, including early exits at the French Open and Wimbledon.

The Belarusian was also defending her world number one ranking in New York, with Elena Rybakina within striking distance after closing to 434 points behind. Sabalenka is defending 2,000 points this fortnight. Rybakina plays 17-year-old American wild card Thea Frodin on Tuesday.

In the match, Osorio handed Sabalenka a break with a double fault in the third game - one of five she had across the opening set - and slipped 4-1 behind as Sabalenka converted another break point with an unreturnable backhand. The Colombian trimmed the lead to 4-2 but could not gain momentum, and her racket went flying in a futile attempt to reach Sabalenka's perfectly placed drop shot on break point in the seventh game.

After trading early breaks in the second set, Sabalenka wore down Osorio's defence to secure the pivotal break in the ninth game, closing it out with an unreturnable serve and a subdued celebration. Sabalenka finished with four aces and converted three of five break points, winning 77 per cent of her first-serve points.