Seven-time Wimbledon champion Serena Williams recovered from being a set down to beat teenage qualifier Kaja Juvan and reach the third round.

Williams was surprised by the 18-year-old world number 133 from Slovenia, who twice broke serve to win the first set.

The 11th seed, 37, responded to take control in the second and eventually closed out the decider for a 2-6 6-2 6-4 victory in one hour 36 minutes.

"She played well and I started out a little slow," said the American.

"I like the pressure. I would rather be in this position than any other and I play best when I am down sometimes. I am a fighter."

Williams, who last won Wimbledon in 2016, will face German 18th seed Julia Gorges in the third round.

She is looking to equal Australian Margaret Court's all-time record of 24 Grand Slam singles titles but has struggled with a knee injury this year.

The American saw off Italy's Giulia Gatto-Monticone in straight sets in the opening round but was given a sterner test by a player who was not born when she claimed the first of her 23 major titles at the US Open in 1999.

Williams lost her opening service game of the match and slipped 0-3 behind, before sending a smashed overhead volley into the net on set point as Juvan clinched the opener in 27 minutes.

Williams recovered to dominate the second set as her opponent, who beat Czech Kristyna Pliskova to reach the second round of a Slam for the first time, appeared to tire.

After twice breaking in the final set, Williams looked to be in full control and served for the match at 5-2 - only for the resilient Juvan to respond with a break of her own.

But the Slovenian was unable to stop an ace on match point and Williams sealed her progression.

Williams will now begin her mixed doubles campaign alongside former British number one Andy Murray on Friday.

"I am excited to play with a British icon like Andy," she said.

"It's going to be incredibly amazing and I feel honoured to share the court with him. Maybe I can learn a thing or two."