World number one and defending women's singles champion Serena Williams became the latest casualty at the Rio Olympics, losing to Elina Svitolina in the third round.
Seemingly bothered by a shoulder injury, the 22-time grand slam champion suffered a surprise 6-4 6-3 defeat at the Olympic Tennis Centre on Tuesday.
Williams joined Novak Djokovic, who is out of the singles and doubles, in making an early exit in Brazil, having also lost in the doubles with sister Venus.
A four-time gold medallist, including in the singles in London, Williams was below her best against the persistent Svitolina.
The American had 37 unforced errors to lose in one hour, 12 minutes in a huge shock against Svitolina, the world number 20 from Ukraine.
Svitolina had won just one set in four previous losses to Williams, but doubled that tally thanks to the 34-year-old's early errors.
The 21-year-old broke twice in the opener - doing so for the second time in the seventh game - after making a fine start.
Svitolina took a 3-1 lead in the second set, but gifted the break back via two double faults in the sixth game.
Williams had serving troubles of her own with five double faults in the next game on her way to crashing out.
Svitolina faces Petra Kvitova in the quarter-finals in a wide-open half of the draw that has also lost Venus and Garbine Muguruza.