Big backhand from Serena Williams and Harmony Tan can only direct it into the tramlines. Williams is building momentum now... that's 0-30, and she senses an opportunity.

Serena Williams opt for the slice, but undercooks it and watches the ball trickle down her side of the net. Again, another big smash gets her out of a hole and she then rallies her way to a hold.

Williams darts to the net but flicks an overhead long. She shakes her fist in celebration after the next serve is batted into the turf by Tan, and then hammers down a smash on the bounce. 30-15.

Serena Williams leaps on a short ball and sweeps it away with a backhand winner. Harmony Tan responds with an ace down the T and then rips another big serve into the strings of Williams. A solid opening hold.

Right then, the decider...

It's Harmony Tan to serve first.

Nick Kyrgios admits spitting in the direction of a 'disrespectful' supporter after beating Britain's Paul Jubb in his first round match at Wimbledon.

Martina Navratilova
Nine-time Wimbledon singles champion on BBC TV

She is here to win it. For her, not winning it is a failure. if she didn't think she could win, she wouldn't be here.

If anyone can do it - it's Serena Williams on this surface because of the way she plays.

Watch Rafael Nadal's best moments as he advances to the second round after beating Francisco Cerundolo over four sets on centre court.

Sloane Stephens, the 2017 US Open champion, has been knocked out of the first round.

The 29-year-old American - who reached the Wimbledon quarter-finals in 2013 - fell at the first hurdle as 19-year-old Qinwen Zheng of China won 7-6 (7-1) 7-5 on Court 15.

Meanwhile, another big-hitter is in trouble on Court Two as 2017 champion Garbine Muguruza has dropped the first set to Belgium's Greet Minnen.

The Spanish ninth seed still has time to stage a comeback, but she will have to wait until Wednesday as the match has been suspended for the night.

To a decider we go!

Ace down the T!

Set point, Serena.

Hello!

Harmony Tan steps in, gets hold of a Serena Williams serves, and slaps it for a winner.

30-30.

Serena Williams goes long on the first point, but back-to-back errors from Harmony Tan take the American to 30-15.

Martina Navratilova
Nine-time Wimbledon singles champion on BBC TV

Williams loves to step into the ball, so the body serve when she has to get out of the way is very effective.

Long goes Serena, and Harmony Tan is on the scoreboard.

Williams will have to serve this set out.

Long goes Serena Williams again in response to a Harmony Tan body serve.

30-15 - oh, and that's a glorious slice from Tan to get to game point.

That's a bit more like it down the line from the Frenchwoman, and Williams goes long in response.

15-15.

Into the net goes a Harmony Tan backhand.

0-15.

Centre Court cheers as Serena Williams swings down an ace, before she follows it up with a double fault.

Tan sends a weary backhand long, handing Williams a couple of game points, and a big ace wraps up a hold.

One more of those and the second set is hers.

With Stefanos Tsitsipas having wrapped up a four-set victory on Court One, the all-Czech encounter between Tereza Martincova and last year's beaten finalist Karolina Pliskova has moved to that court.

It was initially scheduled to be on court three but with light fading, it will be played under the Court One roof.