Defending US Open champion Naomi Osaka passed her opening-round test, producing a powerful performance against Marie Bouzkova 6-4 6-1 on Monday.

All eyes were on Osaka following a difficult couple of months due to mental health concerns as a result of "long bouts of depression" since winning the 2018 US Open.

Osaka withdrew from May's French Open having won her first-round match, after she was fined and threatened with further punishment – and possible expulsion from the grand slam – for skipping obligatory media duties.

The Japanese star subsequently pulled out of Wimbledon before returning for the Olympic Games, though she suffered a surprise loss on home soil in Tokyo and was reduced to tears during a news conference in Cincinnati.

But as fans returned to Flushing Meadows for the first time in two years after the 2020 event was played behind closed doors due to the coronavirus pandemic, Osaka looked comfortable under the Arthur Ashe Stadium lights with the likes of former heavyweight champion Mike Tyson and Hollywood star Alec Baldwin in the crowd.

Bouzkova kept pace with Osaka in the opening set, not overawed by the occasion, but she came unstuck on serve in the 10th game.

While fending off one set point, Bouzkova was unable to save another, slicing a backhand into the net as Osaka closed out the set on her opponent's racquet.

With a set under her belt having reeled off 21 winners in the opener, Osaka stepped it up a gear – winning seven consecutive games before Bouzkova avoided a bagel.

Bouzkova continued to battle but it only delayed the inevitable as Osaka continued her quest for a fourth US Open crown and fifth slam title.

Data slam: Osaka on track to follow in Serena's footsteps

The 23-year-old needed one hour, 33 minutes to book her spot in the next round. Osaka is looking to become the first woman to win consecutive titles at Flushing Meadows since 23-time major champion Serena Williams claimed three in a row from 2012 to 2014.

Osaka is the only woman to win at least one major title over the past four seasons, claiming the Australian Open in 2019 and 2021, as well as the US Open in 2018 and last year.

WINNERS/UNFORCED ERRORS

Osaka – 34/23
Bouzkova – 10/8

ACES/DOUBLE FAULTS

Osaka – 4/1
Bouzkova – 2/2

BREAK POINTS WON

Osaka – 3/6
Bouzkova – 0/8