Olympic Games, London, Day 6 heats:

Rebecca Adlington (GBR), setting up the defence of her Olympic crown, and Lotte Friis (DEN), setting up a rematch of their Shanghai world-title battle of last year, showed good form at the helm of the heats of the 800m freestyle, Friis on 8:21.89 in heat 4 before Adlington swam 8:21.78 in the last heat.

In Shanghai at the world championships last year the two fought stroke for stroke for 15 lengths before Adlington settled the argument with a punishing last lap for the first 800m world crown of her career, one that completed her set of titles over 400m and 800m: Olympic, World, European and Commonwealth. Friis is not the only threat.

Women's 800m freestyle

Katie Ledecky, the 15-year-old American who hot to prominence at US Olympic trials in Omaha a month ago, and Mireia Belmonte (ESP) showed great form in heat 3 on  8:23.84 and 8:25.26 respectively. Ledecky, knowing there were two heats to come, intended to be first home from go, setting a fast sub-world-record pace at the first 100m before settling down into a winning rhythm, Belmonte the only one to stick with her. Left to wait for two heats and the clock, Wendy Trott (RSA) came in third on 8:28.11, Eva Risztov (HUN) on 8:28.98, Ellie Faulkner (GBR) on 8:29.06. 

Heat 4 witnessed a similar pattern, established by one woman, world silver medallist Lotte Friis (DEN) on 59.11 at the first 100m turn, the pace ensuring that she would race alone on her way to an 8:21.89 conclusion and qualification.

Boglarka Kapas (HUN) and Andreina Pinto (VEN) tied for second on 8:26.43, Coralie Balmy (FRA) on 8:27.15, Kristel Kobrich (CHI) on 8:29.55 and already out of the final, as was Faulkner before the last heat took to the water.

Defending champion Rebecca Adlington (GBR) established a solid body-length lead in the first 200m on her way to turning at the half-way mark in 4:09.40, the closest to her Lauren Boyle (NZL) 5m adrift by the 600m mark. 

Adlington pushed on to an 8:21.78 conclusion to secure lane 4 in the final as the home crowd went wild, Boyle on 8:25.91, Shao Yiwen (CHN) on 8:27.78 but locked out of the final, Balmy the last one in with her 8:27.15.

Men's 50m freestyle

Heat 6 woke everyone up: George Bovell (TRI) and Anthony Ervin (USA) shook off the cobwebs of a long wait for the  dash on day six: 21.77 and 21.83. Take that! Andrey Grechin (RUS) was first over 22, by 0.9sec. In response, Roland Schoeman (RSA) led Cullen Jones (USA) 21.92 to 21.95 in heat 7, Andrii Govorov matching Grechin's 22.09, James Magnussen (AUS) on 22.11. 

In the last of eight heats, defending champion Cesar Cielo led Brazilian teammate Bruno Fratus 21.80 to 21.82 to squeeze between Bovell and Ervin for top three places going through to semis, Florent Manaudou (FRA) on the third 22.09 effort of the morning. The top 16 was locked in 22.27 by Australia's Eamon Sullivan. Among those locked out: Stefan Nystrand (SWE), Amaury Leveaux (FRA),  Marco Orsi (ITA), Adam Brown (GBR) and Sergei Fesikov (RUS).

Men's 100m butterfly

The Beijing 2008 rematch is done for this morning: Michael Phelps (USA) Vs Milorad Cavic (SRB), side by side once more in lanes 4 and 5 of heat 6. No 0.01sec in in at this stage - 51.72 for the defending champion heading for a three-peat, 51.90 for Cavic, silver medal winner in Beijing 2008 and Rome 2009 when he and Phelps dipped inside 50sec boosted by the poly in their suits.

Neither were quicker this morning: at the helm of qualifiers is Chad Le Clos, the South African who pipped Phelps by 0.05sec for the 200m crown, his 51.54 in heat 5 before Phelps walked out a national record that wiped 0.63sec off the 52.17 best he set last September. Behind Le Close came Konrad Czerniak (POL), on 51.85, and Steffen Deibler (GER) on 51.92. 

Also among those at the helm was Evgeny Korotyshkin, of Russia, on 51.84 at the helm of heat 4, Tyler McGill (USA) on 51.95 as the last man inside 52sec.

Women's 200m Backstroke

Already in Heat 2 Simona Baumrtova of the Czech Republic set the standard at 2:10.03. After which America's Elizabeth Beisel - silver medalist in the 400 IM on Day 1 - decided there was no fooling around. She swam a scorching 2:07.82 to post the fastest time, Alexiane Castel of France touched second in 2:08.92, just ahead of Canadian record-holder in the event Sinead Russell on 2:09.04.

Jenny Mensing of Germany looked promising in the first 100 of heat 4 - but couldn't hold the pace. Belinda Hocking of Australia took over in the second 100 to take the heat in 2:08.75, followed by Ukraine's Daryna Zevina in 2:09.40 - and Britain's Elizabeth Simmonds well down in 4th place in 2:10.37.

Missy Franklin, who heads into the 100 freestyle final tonight for a potential 4th medal, took to the water in the fifth and final heat to rule the field: she posted 2:07.54 - with defending champion Kirsty Coventry of Zimbabwe right behind her in 2:08.14.

Coventry won this event in Athens and in Beijing - and is the only woman at the meet with the chance to three-peat in an event - but Franklin will be tough to beat.

The semis line up with Franklin in first, followed by Beisel, and Coventry. Canada's Russell is in a comfortable 7th and 2:10.60 was the cut to make to get in - that posted by Sharon van Rouwendaal of the Netherlands for 16th place.