NEW HAVEN, Conn. (AP) Madison Keys advanced to the second round of the Connecticut Open with a victory over Elina Svitolina on Monday.
Keys battled back from a 0-4 deficit to win the first set 7-6 (7-4) and was leading 4-2 in the second when Svitolina retired due to a lower back injury.
''I'm really happy with how I turned things around today,'' Keys said. ''I kind of just started (hitting) balls on the court, it wasn't rocket science. I stopped missing so many.''
Keys, who reached the top 20 after advancing to the Australian Open semifinals earlier this year, is the second-highest ranked American (19th) behind Serena Williams.
In other matches, Canada's Eugenie Bouchard was upset by Italy's Roberta Vinci 6-1, 6-0. France's Kristina Mladenovic also knocked off eighth-seeded Sara Errani from Italy 6-2, 4-6, 6-4.
Ukraine's Olga Savchuk and France's Caroline Garcia also advanced to the second round.