Karlovic, Zverev advance at Stockholm Open
Published 4:34 pm, Wednesday, October 19, 2016
Ymer, who upset Fernando Verdasco in the first round for his first ATP tour victory, thrilled the home crowd by winning the first set but ultimately couldn't match the power of his Croatian opponent.
Karlovic hit 16 aces to win 4-6, 6-4, 6-4 in 1 hour, 47 minutes.
Alexander Zverev of Germany is also through to the quarterfinals after beating Frenchman Adrian Mannarino 7-5, 6-4.
In first-round action, last year's Stockholm Open finalist Jack Sock of the United States beat Malek Jaziri of Tunisia 3-6, 6-3, 7-6 (5).
Argentina's Juan Martin del Potro and Jurgen Zopp of Estonia also advanced to the second round.