“It was a tough day, a disappointing day. I can’t lie about that,” Barty told the Seven Network after her defeat to Sorribes Tormo, in which the Australian made 55 unforced errors to her opponent’s 13
“It was just loose. I knew I wanted to try and take the match on today and it was going to be a fine line of pushing too hard and not getting stuck into patterns I didn’t want to get stuck in.
“[I was] just too erratic today, I wasn’t able to make enough balls.”
Meanwhile, Murray’s exit leaves Liam Broady as the sole Briton remaining in the singles, following Heather Watson’s first-round defeat on Saturday.
Broady battled past Argentina’s Francisco Cerundolo 7-5 6-7 (4-7) 6-2 in three hours three minutes to set up a seond-round meeting with Wimbledon semi-finalist Hubert Hurkacz of Poland.
Elsewhere in the Games on Sunday, taekwondo star Jade Jones saw her bid for a third successive Olympic gold ended by a first-round defeat to Kimia Alizadeh of the Olympic Refugee Team.