Hopes are high for Adam Peaty to break through the medal barrier for Team GB in Rio later after the swimming sensation left his own world record in his wake.
Despite it being his first Olympic final, the 21-year-old is hot favourite to win in the men's 100m breaststroke - Britain's first games swimming gold for decades.
There are also high hopes for Jazz Carlin, Team GB's contender in the 400m freestyle, as attention turns to the pool after medals continued to elude British athletes.
On Sunday Lizzie Armitstead could only manage fifth in the women's road race and fencer Richard Kruse lost an incredibly close bronze medal match in the foil.
Armitstead was one of the favourites for glory in the cycling but missed out in the 137-kilometres race as Holland's Anna van der Breggen won a dramatic gold.
Her compatriot Annemiek van Vleuten suffered three small fractures to her spine and is in intensive care at a Rio hospital after crashing during the race while she was leading. Doctors said she was conscious and speaking.
There was heartache for fencer Kruse, who in his fourth Olympics came agonisingly close to winning his first medal.
Kruse was beaten 15-13 by Russian Timur Safin in the bronze medal play-off match, despite a spectacular comeback from 12-5 down to move within two points of victory at the Rio Olympic Park.
Divers Alicia Blagg and Rebecca Gallantree were also left frustrated after finishing sixth in the three metre synchro final.
The pair were in third after two rounds but ended in sixth as the Chinese pair of Wu Minxia and Shi Tingmao dominated, Minxia becoming the first diver to win five Olympic gold medals and the oldest female champion in the sport.
Elsewhere, Andy Murray eased past Viktor Troicki as he got the defence of his Olympic men's title under way, winning in straight sets 6-3 6-2.
The win was Murray's 13th in a row and seventh at the Olympics, and he will look to extend the run when he faces Argentina's Juan Monaco in the second round.
Britain's women gymnastics survived a scare when Ellie Downie was injured when she fell on her neck during her floor routine.
Downie said she heard a crunch and was put in a wheelchair, but later returned to help her team qualify for the final.
Team GB's women's rugby sevens team continued their imperious form, cruising past Fiji 26-7 in the quarter-finals to set up a tough semi-final against one of the favourites New Zealand, who squeezed past the USA in their quarter-final.
But there was frustration for Great Britain's men's hockey team, who were held to a 2-2 draw in a group stage match by New Zealand.
Canoe slalom athlete Joe Clarke qualified in second for Wednesday's semi-final, recovering brilliantly after a 50-second penalty in his first run.
In the table tennis Liam Pitchford and Paul Drinkhall safely negotiated their way through the second round.
Earlier in the day the Olympic rowing programme was left in disarray after strong winds forced organisers to postpone racing.
Boats were being blown off course and swamped in choppy waters during practice earlier on Sunday, and after repeated delays World Rowing announced that racing was being called off.