It's the ball I feel sorry for. That is an incredible rally. Side to side, corner to corner. Nishikori into the net, Murray on the stretch. In, out? On the line! Murray celebrating from the floor. Another match point...

Image source, Reuters

Nishikori makes us wait, climbing us into Murray's second serve. Where's this been all day?

Murray has new balls on his strings, but that only helps Nishikori to launch himself into a line-seeking return. Murray, though, is rushing to wrap this up. Two match points...

Nishikori's serve and forehand get him through a hold, sparking much noise on Centre Court. He sits on his chair, contemplating what drink he is going to order in the Last Chance Saloon. Murray to serve for the match.

That may be sooner, rather than later (though not before 18:00). Breeze of a hold for Murray. The defending champ is one game away from the final.

Speaking of Nadal, this was the moment that he and Marc Lopez beat Romania's Florin Mergea and Horia Tecau to win gold in the men's doubles.

Nadal and Del Potro are on court after the Murray-Nishikori match.

Nishikori hangs on, finding the line with a forehand and celebrating with a clench of the fist. A big Japanese contingent in the crowd cheer, while the neutrals are baiting Murray too. His antics have not gone down well. Remember, the winner of this plays either Rafael Nadal or Juan Martin del Potro in the final. 

Andy Murray has been through the wringer on each of the past two days, needing deciding sets against both Fabio Fognini and Steve Johnson. There looks to be no sign of that sort of drama today. A set and a break up, he's pressuring the Japanese serve once more. In the Rio sunshine, Nishikori is desperately battling against what would be a terminal break.

Aimee Lewis
BBC Sport in Rio

"Nishikori! Nishikori!" chant the crowd, Japanese, Brazilian, Argentine fans all in unison. Defending champion Andy Murray is closing in on victory, but the spectators want this match to go on and on. A break to love, a hold to love, the world number two within touching distance of that gold-medal match. 

Image source, .

That was Mike Henson, this is Stephan Shemilt. 

Saturday has already given Great Britain one gold and one silver medal and promises plenty more.

Andy Murray can't win a medal today, but he can make sure of one...

The morning session in the Olympic Stadium finishes with Christoph Harting accepting his discus gold with a theatrical bow worthy of the West End.

The action resumes at midnight BST.

Here are the times you need to know:

Midnight: Heptathlon javelin

0053 BST: Long jump final featuring Greg Rutherford

0127 BST: Men's 10,000m final featuring Mo Farah

02:37 BST: Women's 100m final

03:18 BST: Heptathlon 800m - the final event for Jessica Ennis-Hill and Katarina Johnson-Thompson

Set your alarms now. And that will need to be plural.

Murray is serving well and in control but still finds time for a semantic debate with umipre Carlos Ramos after receiving a code violation - they debate whether he said "Stupid umpire" or Stupid umpiring".   

Akani Simbine of South Africa wins the final 100m heat in a time of 10.14 seconds.

Great Britain's James Dasaolu gets through as one of the fastest losers as does Jimmy Vicaut and Christophe LeMaitre.

The final time sheets show the United States' Justin Gatlin was quickest in 10.01 with defending champion Usain Bolt back in 10.07.

Both had plenty of nitro boost to burn though.

Denise Lewis
Olympic heptathlon gold medallist on BBC TV

Thiam wanted to remind us that she is still here.

It is very exciting. I still hope we can get two medals at the end of the day.

The heptathlon field are off to the javelin oche.

Tom Fordyce is the man with the stats you need to know...

Five metres worse in the javelin PBs, 10 seconds better in the 800m.

That adds up to a real battle for gold for Jessica Ennis-Hill and Nafi Thiam. 

Benjamin Rae: Usain Bolt looks like he has a world record in him given 10.07 jog there. Incredible athlete.

Aimee Lewis
BBC Sport in Rio

From the velodrome to Centre Court where Andy Murray is making Kei Nishikori look like an average Tour player. Thirty minutes is all it took for the defending champion to win the first set.

There aren't as many Union flags dotted around as there have been for previous round, but the Briton is getting plenty of support nevertheless. "Come on, Andy," yell a few fans from the crowd. A straight-sets win is on the cards.

Image source, .

"I'm not convinced, I'm going to check after the match."

Classic Andy Murray so far - playing terrifically to move into a 6-1 lead against Kei Nishikori, but the Briton finds time to give Carlos Ramos a stern talking to at the changeover after the umpire handed out a time violation. 

Alistair Magowan
BBC Sport in Rio

Image source, BBC Sport

Hugs, cheers and tears in amongst the GB fans and families as they watch the women's eight win their first Olympic medal and then the men's crew take gold with a stunning performance. 

GB medalists Heather Stanning, the men's four and Vicky Thornley and Katherine Grainger have all been watching and the feeling of cameraderie is palpable. 

I think there is going to be some serious celebrating over the next few days.