Fifth seeded Roberto Bautista Agut and eight seeded Andreas Seppi are the first players to reach the quarterfinals of the Kremlin Cup in Russia on Wednesday.

The 26-year-old Spaniard had to earn every point as he defeated Australian Sam Groth in two straight sets 7(7)-6(5) 7(7)-6(4) in a match that lasted an hour and 24 minutes.

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Groth is best known for hitting the fastest serve on record at 163.4 mph. He dished out a total of 19 service aces and saved to break points he faced.

Bautista Agut will face the winner of the matchup between top seeded Milos Raonic and Lithuanian qualifier Ricardas Berankis.

The 2012 champion Seppi also advanced to the quarters after defeating Croatian Ivan Dodig also in straight sets 7-5 7(7)-6(3).

The Italian will go up against the victor of the match between third seeded Ernests Gulbis and Daniel Gimeno-Traver.

In other matches, sixth seeded Tommy Robredo advanced to the second round after winning his opening match against Serbian qualifier Pedja Krstin 7(8)-6(6) 6-4.

Robredo delivered seven aces during the match and will face another Serbian Filip Krajinovic next.

Seventh seeded home crowd favorite Mikhail Youzhny won his opening match against compatriot Victor Baluda after breaking the qualifier once in both sets 6-3 6-4.

Youzhny, 32, won 21 of his 26 first serves and 66 percent on his second serves.

The 2009 title holder will face Juan Monaco of Argentina next which he also played at last week's Shanghai Rolex Masters. Youzhny won the match after dropping the first set.

"We played in Shanghai last week," Youzhny said. "He is in a good shape now. We had a very tough match; I think this one is also going to be very tough."

Last year's runner-up, Mikhail Kukushkin of Kazakhstan won over Russian wild card entry Karen Khachanov in three sets 6(3)-7(7) 6-0 6-2 to setup a second round encounter against fourth seeded Fabio Fognini of Italy.

Frenchman Richard Gasquet was the defending champion, but withdrew before the tournament began.

TagsMikhail Youzhny, Milos Raonic, Roberto Bautista Agut, Tommy Robredo