Emma Raducanu admitted she has been "too tense" in recent defeats and is aiming to play more freely as she prepares to defend her US Open title.

Raducanu has struggled to follow up last year's shock win at Flushing Meadow, but she appears to have hit form at just the right time.

The 19-year-old has beaten both Serena Williams and Victoria Azarenka in straight sets during this week's Western and Southern Open in Cincinnati, dropping just four games against Williams and two against Azarenka.

Her win against Azarenka on Wednesday was just Raducanu's third career victory against a top-25 opponent, after beating Belinda Bencic and Maria Sakkari on her way to winning last year's US Open.

Speaking after her win against the Belarusian, Raducanu said: "I think I have tried a lot of things, and this year I think some matches, I have lost a lot of matches from leading situations and probably just played too tense.

"I think that I just need to swing, and I just said that these two tournaments, or this tournament especially, I'm just going to swing freely and take that and see what happens."

Raducanu also said she will wait until after the tournament to reflect on beating two multiple grand slam champions with relative ease.

"I think after the tournament I actually have to take a step back and be like, 'Look, you just beat two unbelievable champions'," she said. "It's a pretty good achievement. You know how difficult the wins are to come by."

The number 10 seed will face seventh seed Jessica Pegula in the third round in Cincinnati on Thursday.