Haas suffers second-round defeat
Top seed Tommy Haas fell out of the ATP Delray Beach International Tennis Championship with a second-round defeat to qualifier Steve Johnson.
World number 12 Haas of Germany suffered a 6-4 2-6 7-6 loss to the world number 142 and takes, who meets Spaniard Feliciano Lopez in the third round.
The 24-year-old claimed his second career win over a top-20 player to build on his best start to an ATP World Tour season on Wednesday.
Fourth seed Kevin Anderson, who won the tournament in 2012, was granted a place in the quarter-finals when Ivo Karlovic retired from their second-round clash with a stomach virus after just one game.
Anderson, 27, faces Marinko Matosevic next after the Australian advanced to his third quarter-final of the season.
Matosevic was leading compatriot Lleyton Hewitt 7-6 before the former world number one was forced to retire with a shoulder injury.
While sixth seed Feliciano Lopez was made to work hard for his second-round win, fighting from a set down to defeat Adrian Mannarino 4-6 6-4 6-2.
In the first round, seventh seeded Croatian Marin Cilic kept up his good run of form as he made a winning start by seeing off Benjamin Becker 6-1 6-3 in just under an hour 55 minutes to progress.