Madeline Groves has added silver to Australia's medal tally in the pool after narrowly missing the gold in the women's 200 metres butterfly at the Rio Olympics.

Key points: Women's 4x200m freestyle relay team wins silver medal

Women's 4x200m freestyle relay team wins silver medal Groves misses out on gold by 0.03 of a second

Groves misses out on gold by 0.03 of a second Cate Campbell through to the 100m freestyle final with time of 52.71

Groves was out-touched by just 0.03 of a second, with Spain's Mireia Belmonte Garcia beating the Australian home 2:04.85 to 2:04.88 in the final at the Olympic Aquatics Stadium.

Australia won another silver on night five of the swimming program, with its 4x200m freestyle relay team finishing second to the Katie Ledecky-led United States quartet.

Leah Neale, Emma McKeon, Bronte Barratt and Tamsin Cook posted a time of 7:44.87, with the Americans winning in 7:43.03.

It gives McKeon the full set of medals in Rio, following gold in the 4x100m freestyle relay and bronze in the 200m freestyle, while Ledecky now has three gold medals at these Games.

Earlier, Cate Campbell confirmed her favouritism for the women's 100m freestyle gold after breaking the Olympic record she set in the heats with a slick time of 52.71 in her semi-final.

Australia's women's 4x200m freestyle team held on for a well-earned silver medal. ( AP: Michael Sohn )

Groves swam a personal best in becoming Australia's ninth Olympic medallist in the women's 200m butterfly, having produced a courageous display in the final when she set the pace for the field through the first half of the race.

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She led Belmonte Garcia by almost a full second after 50 metres and was still in front at the midway but the Spaniard made her move to take the lead with a lap remaining.

Groves had appeared to be tiring but she found renewed energy in the final 50 metres to take the fight up to Belmonte Garcia, while Japan's world champion and eventual bronze medallist Natsumi Hoshi was also in contention.

It became a blanket finish, with Belmonte Garcia just edging out the 21-year-old Australian, who can be justly proud of her performance following the challenges she has faced in her young career.

She briefly gave away swimming in her late teens and even after returning she struggled with injury and health issues, which were holding her back from realising her enormous potential.

Groves was satisfied with the execution of her pre-race plan, admitting she had little left in the tank.

"I am so happy with how it went.

"It just means so much to even be here, as four years ago I was in year 12 and wasn't even swimming, I don't know what I was doing.

"I absolutely couldn't have done this without my coach Michael Bohl. He's been my biggest supporter for so long and he's always been so encouraging and understanding of me."

Australia's Madeline Groves competes to place second in the women's 200m butterfly final. ( AFP: Martin Bureau )

The Michael Bohl-trained Groves, nicknamed "Mad Dog", underperformed at last year's Kazan world championships, where she unable to make the final, but clicked into gear in 2016, as she illustrated in emphatic fashion at the Olympic trials when she swam what was a world-leading time of 2:05.41.

Another Australian, Brianna Throssell (2:07.87), was eighth in the 200m butterfly final.

Campbell signals intention for 100m gold

Cate Campbell is into the 100m women's freestyle final. ( AFP: Odd Andersen )

Campbell's Rio tilt could hardly have started in much better fashion, following gold in the 4x100m freestyle relay on the opening night of competition and now back-to-back Olympic records in the individual event.

She sliced 0.07 off her mark from the heats, doing so with ease to lead qualifying for Thursday night's (local time) final.

Canada's Penny Oleksiak was only 0.01 behind Campbell, but the Australian world record holder gave the impression she had plenty in reserve.

Should she win gold in the final, it would give Australia the first women's and men's double in the 100m freestyle since Dawn Fraser and John Devitt claimed respective victories at the 1960 Rome Olympics.

Campbell's sister Bronte, the reigning world champion, progressed via a time of 53.29 in finishing second to American Simone Manuel (53.11) in the first semi-final.

Another of Australia's medal contenders, Taylor McKeown, won her semi-final of the women's 200m breaststroke to 2:21.69 to lead qualifying for the final.