Top seed John Isner coasts to victory at Citi Open

The 31-year-old sent down 14 aces and lost only three points on his first serve as he coasted through the second-round encounter in just 63 minutes.

Isner will face 15th seed Marcos Baghdatis in the third round after he saved all four break points face on the way to a 6-2 6-4 win over Australia's John Millman.

Third seed Bernard Tomic saw off home hope Donald Young 7-6 (7/4) 6-3 to set up a third-round clash with 13th seed Ivo Karlovic.

Sixth seed Jack Sock will play Great Britain's Dan Evans in the third round after he overcame Lukas Lacko 7-6 (7/1) 6-4 and Ryan Harrison upset the number 10 seed Viktor Troicki with a 7-6 (7/4) 6-4 triumph.

At the Generali Open in Kitzbuhel, Jurgen Melzer stunned top seed and fellow Austrian Dominic Thiem with a 6-3 7-5 victory.

It was Melzer's first victory over a top 10 player for more than five years and he told reporters: "I think I showed almost perfect tennis, which one needs to play when facing Dominic. I also used the advantage that he had all the pressure on him."

Melzer will face his younger brother Gerald in the quarter-final following his convincing 6-3 6-1 win over Daniel Gimeno-Traver.

Second seed Philipp Kohlschreiber was also shocked, beaten 6-4 6-4 by Karen Khachanov.

There was no such trouble though for the fourth-seeded Paolo Lorenzi, who eased to a 6-2 6-2 win over Roberto Carballes Baena.

Eighth seed Jan-Lennard Struff came through a close match with Daniel Munoz de la Nava 7-5 7-5.

Third seed Jeremy Chardy required just 43 minutes to advance to the quarter-finals of the Croatia Open in Umag.

Chardy dropped just six points in the second set as he prevailed 6-2 6-0, while fourth seed Fabio Fognini also moved on serenely, seeing off Renzo Olivo 6-4 6-1.

Damir Dzumhur came through 4-6 6-1 6-2 against Thomas Fabbiano and Carlos Belocq advanced after Jiri Vesely retired when 7-5 3-0 down.

At the Swiss Open in Gstaad, top seed Feliciano Lopez overcame qualifier Jan Mertl 7-6 (7/4) 6-4.

Elias Ymer will be waiting for him after beating Konstantin Kravchuk 2-6 7-6 (7/5) 7-5, while Albert Ramos-Vinolas beat Tristan Lamasine 6-4 6-2.

In the final match of the day, Paul-Henri Mathieu ended the interest of local wild card Henri Laaksonen with a 6-1 6-4 victory.