Ash Barty has followed up her shock women's singles defeat by crashing out of the women's doubles after an epic clash with Czech pair Barbora Krejcikova and Katerina Siniakova.

World number one Barty was stunned in the first round of the women's singles on Sunday by Spain's Sara Sorribes Tormo but teamed up with Storm Sanders in the doubles, with the Australian pair reaching the quarter-finals.

However, Krejcikova and Siniakova proved too strong in a three-set thriller, winning 3-6 6-4 10-7.

"You never quite have their measure,” Barty said. "It's disappointing but there's only a couple of points in that match, here and there and it's a different result.

"We did everything right today but just weren't able to win those big points when it mattered most."

Barty's medal hopes are now entirely focused on the mixed doubles, where she has partnered with John Peers.

Andy Murray's bid to become the first male to win four Olympic tennis medals ended with defeat to Croatia's Marin Cilic and Ivan Dogic in the men's doubles.

Murray, teaming up with Joe Salisbury, went down in two hours and 18 minutes after also winning the first set. The Croatian pair won 4-6 7-6 (7-2) 10-7.

The two-time Olympic gold medalist had withdrawn from the men's singles on Sunday due to a right quad injury, preferring to focus on playing doubles. TeamGB have not fielded a mixed doubles team.

TITMUS DOUBLES UP, LEDECKY LIFTS FOR GOLD

Ariarne Titmus backed up her women's 400m freestyle gold medal from Monday with another triumph, getting the better of rival Katie Ledecky to win the 200m free.

The 20-year-old Australian won the final ahead of Hong Kong's Siobhan Bernadette Haughey and Canada's Penny Oleksiak, while Ledecky finished back in fifth.

Ledecky would claim her sixth Olympic gold medal, triumphing in the women's 1500m free, with the US claiming a rare one-two as Erica Sullivan grabbed the silver ahead of Germany's Sarah Kohler.

After being beaten twice by Titmus earlier in the meet, Ledecky said: "I approach each race with a belief in myself. It's the attitude I've always had that's why I've been so successful. Anything can happen, [the attitude I go in with is] I can beat the world record in this race.

Japan's Yui Ohashi won the women's 200m individual medley, Hungarian favourite Kristof Milak powered to victory in the men's 200m butterfly and Great Britain triumphed in the men's 4x200m freestyle relay.

STEERING ERROR COSTS GB IN ROWING

Australia claimed two gold medals in the rowing at Sea Forest Waterway as Great Britain were left to lament a wayward finish in the men's four final.

Australian quartet Alexander Purnell, Spencer Turrin, Jack Hargreaves and Alexander Hill won in 5:42:76 ahead of Romania and Italy who claimed silver and bronze respectively.

Italy's late charge almost saw a collision with Great Britain, who finished in fourth, after veering towards the neighbouring Italian boat, narrowly avoiding a clash of oars.

GB's Oliver Cook, who steered the men's coxless four, told BBC Sport: "I do (have the steering). I need to diagnose it but I feel I screwed up a bit and as I was closing in at the end and taking big strokes at the end going for the line I forgot the steering and that’s what cost us to be honest, cost us a medal."

Australia also won the women's four narrowly ahead of the Netherlands by 0:34 seconds, with Ireland claiming the bronze more than five seconds back.

Romania secured its first gold medal at the Tokyo Olympics by winning the women's double sculls final, while France triumphed in the men's equivalent.

The Netherlands and China triumphed in the men's and women's quadruple sculls finals respectively.

RADRADRA DREAMING OF FIJI SEVENS GOLD

New Zealand will take on 2016 gold medalists Fiji in the final of the men's rugby sevens on Wednesday evening.

Fiji went through to the gold medal match with a 26-14 triumph over Argentina, who will take on Great Britain for bronze.

New Zealand were too strong for the British, winning 29-7 in their semi-final, with two tries each to captain Scott Curry and Regan Ware.

Former NRL star Semi Radradra, who plays for Fiji after switching codes in 2017 and scored a try against Argentina, said: "Playing in the Olympics is a blessing for me. I never knew I would be here.

"I think it is everyone's highlight to win a gold medal in the Olympics. That is our aim and we try to give back to our people at home."

USA RESTORES CONFIDENCE IN BASKETBALL

Team USA restored some confidence following their first-up loss to France with a comprehensive 120-66 thrashing of Iran in men's basketball.

USA played fast throughout, wasting no time in offense, with Damian Lillard top scoring with 21 points, all from beyond the arc.

Chicago Bulls guard Zach LaVine had eight assists along with his 13 points while Devin Booker, who played in the NBA Finals last week, scored 16 points and had five rebounds and three steals.

USA head coach Gregg Popovich rotated his roster on and off the court, sharing minutes, as hos team piled on 38 points in the last quarter to round out a comprehensive victory.

In Group B, Germany defeated Nigeria 99-92 despite Jordan Nowra's 33-point haul.