- Katie Ledecky wins 200m freestyle heat, well shy of world-record time. Michael Phelps reaches men's 200m freestyle semi-final.
- Archery top seed Kim Woo-jin suffers shock elimination in first round.
- Argentine golfer Emiliano Grillo without his clubs, which were lost by an airline, three days out from the competition.
QUOTES OF THE DAY
"We continue working, our Paralympic team continues preparations for the Games," Russian Paralympic Committee president Vladimir Lukin told Tass, following Sunday's blanket ban of Russia's Paralympians over state-sponsored doping.
"It's just as well I got beaten because I would've been embarrassed the next fight." - Irish lightweight boxer Paddy Barnes had targeted gold pre-Games, but lost his opening bout to Samuel Carmona Heredia.
"I think that was probably going to be my hardest swim of the week so I'm glad it's over with," Ledecky said after winning her 200m freestyle heat, having broken the 400m world record the day before.
Niccolo Campriani won the first gold of the day in the men's 10 metre air rifle, with further shooting honours going to Anton Glasnovic in the men's trap.
COMING UP: The King takes court and rugby history
There are still 20 sets of medals up for grabs today, with highlights likely to come in the men's team all-around gymnastics final, 'King'Kohei Uchimura in action.
Australia and New Zealand's women will contest the first Olympic rugby sevens final.
Ledecky was well off Federica Pellegrini's record as she qualified for the 200m freestyle final fastest, but don't count out her raising the heat when it matters most. In the same event for the men, Phelps goes in search of a spot in the final in his quest for a 20th Olympic gold.
Spare a thought for Kazakh rower Vladislav Yakovlev.
Perhaps nerves were to blame after high winds led to action being postponed on Sunday. Just 10 strokes into the men's single sculls repechage, Yakolev was in the water after capsizing.
It is thought to be the quickest capsizing in an Olympic race.