Serena Williams scraped into the third round at Wimbledon, while her older sister Venus was also pushed all the way on a weather-truncated Friday.

Teenager Daria Kasatkina was beaten 7-5 4-6 10-8 by Venus in a Court One epic, while Serena beat fellow American Christina McHale 6-7 (7-9) 6-2 6-4 on Centre Court.

Only seven women's games were completed on Friday as rain once again interfered with the tournament, prompting organisers to move some matches to Sunday for only the fourth time in the event's long history.

SERENA FAR FROM SERENE

Wimbledon is the last grand slam title still in Serena's possession, and she was perhaps fortunate that remained the case after a sluggish showing.

A string of errors in the first set helped McHale to a couple of breaks, although the younger American still needed a tie-break to go ahead.

Warned by the referee and booed by the crowd for a tantrum, Williams finally channelled her frustrations correctly in the final two sets to book a third-round meeting with Annika Beck - a 6-2 6-1 victor over Aliaksandra Sasnovich.

Post-match, Serena conceded she had not been at her best.

"There were times where I was down and out. I just kept fighting. That's what I know I can do best. I knew that I could count on that, rely on that."

MATCH POINT … RAIN STOPS PLAY!

Venus Williams may have allowed herself a short exhale when 40-30 and 7-6 up against Kasatkina in the final set of their match.

But then, the rain.

Play was suspended for over an hour, and Venus put the delayed match point into the net, Kasatkina holding on.

Facing a player who was just 47 days old when he made her Wimbledon debut, Venus needed to use all her wit and guile, but finally saw off the Russian with her third match point - around an hour and a half after her first.

Venus said: "I can't say that I've ever had a rain delay at match point.  Probably not ideal.  She handled it well.  She played smart. 

"It was just, I guess, non-stop action.  It was like a Hollywood script."