Serena Williams won her first Gland Slam match following the birth of her daughter in September, beating Kristyna Pliskova in straight sets.
Williams' 7–6 (4), 6–4 victory was her first Grand Slam victory since winning the 2017 Australian Open.
She will face No. 17 seed Ashleigh Barty in the second round.
WIlliams missed the subsequent three Grand Slams in 2017 due to her pregnancy, seeing her WTA ranking drop to 453rd in the world.
She went 2-2 in tour matches this year, and had not played since March.
The 36-year-old unseeded Williams is seeking her 24th Grand Slam title.