I've probably gone a bit early with my build-up for the swimming because we actually have around two hours until the action in the pool begins. 

There is, though, still sport going on and a gold medal up for grabs in the weightlifting. Let's check in on that.

Image source, Getty Images

Cast your mind back to the memorable moments of London 2012. 

There was Super Saturday, Andy Murray winning at Wimbledon and David Beckham on a speedboat. There was also a shock in the pool as Chad le Clos upset Olympic champion and world record holder Michael Phelps, beating him in the 200m butterfly. 

So began a rivalry that brings us to this moment, Phelps vs Le Clos part two. It's a grudge match that kicked off in feisty fashion with Phelps appearing to give Le Clos the most evil of evil stares in yesterday's semi-final.

Image source, Twitter/NBC

They are back in the pool at 02:28 BST for the men's 200m butterfly final, so brew up and get settled in. There could be fireworks.

Epic stint Stephan. As epic, some would say, as the swimming we have coming up tonight. 

Anyone up for a London 2012 rematch?

Right then, that Serena Williams defeat is my last action of the day. Gary Rose will be here into the wee small hours to talk through another golden night in the swimming pool.

Karthi Gnanasegaram
BBC radio 5 live reporter

Serena had already gone out of the doubles, so she wanted to make sure she got one gold medal in the singles. The crowd here are quite strange in that they seem not quite tennis fans so they boo and cheer at strange times. They booed her double faults and I don't think she liked that.

Jack[SDMN]: So many upsets in the tennis so far

David Barron: Just saw Serena Williams knocked out of the women's tennis singles. Blimey that's a shock

teresa engley: Wow; 2 great tennis matches today. Konta's win and Serena going out.

Tom Fordyce
Chief sports writer in Rio

Serena gone from Olympic singles - straight sets shocker to Elina Svitolina. Normally indomitable serve reduced to rubble.

That's it! Serena Williams goes out! A wild forehand confirms that the defending champion is beaten by Ukraine's Elina Svitolina.

Svitolina slumps into her chair, shaking her head, barely able to believe it. Williams is off the court in a flash, just about managing a wave to the crowd. A uncharacteristic performance doesn't even come close. She was a shadow of herself out there tonight.

Williams is almost in tears on the baseline here. Yet another double fault. Three match points...

Svitolina is being watched by lots of blue-and-yellow clad Ukrainian athletes. She holds to love. Serena will serve to stay in the Olympics.

Aimee Lewis
BBC Sport in Rio

There aren't many empty seats on Centre Court for Serena Williams' night match with Elina Svitolina. The world number one is fighting for survival, a set down and toiling in the second set. Far too many unforced errors. But the crowd are firmly in her camp, roaring points won, groaning at points lost. A carnival atmosphere, you could say. 

Image source, .

Incredible. Absolutely incredible.

Serena Williams has just served five (yes, five) double faults in the same game to give away what could be a crucial break. As she sits on her chair, she looks close to tears. At the moment, the GOAT is going out.

What is going on out there? For some reason, Serena is mixing booming aces with double faults, three of them. Shrugging her shoulders, she gives away a break point...

Now then, is Serena awaking from her slumber? Error-strewn so far, the GOAT steps in to gobble up a soft second serve, then earns herself a break point. A double fault from the under-pressure Svitolina, her second of the game, gives up the precious break.

Serena holds with the aid of a delicious drop shot and an errant Svitolina backhand. Still, the Ukrainian only has to hold three times (easier said than done, I know) to pull off something special. Remember, Novak Djokovic has already been dumped out of the men's singles.

Leon Taylor
Olympic diving silver medallist on BBC TV

"I wish I had an answer to why the pool was green. As I arrived, it was blue but went greener and greener. It looked the colour of a gherkin.

"There might be a bit of imbalance with algae.

"Tonia Couch and Lois Toulson's third and fourth dives kept them in the contest until the last round. They needed the best dive of their careers but it was not to be for a medal."

Elina Svitolina, it should be noted, is not without pedigree. The 21-year-old is the world number 20 and has won four WTA titles. She has consolidated her break of serve and is three games from putting Serena out of these Games.