Karlovic serve too much for Dimitrov

Croatian giant Ivo Karlovic served 18 aces when he beat Grigor Dimitrov 7-6 (7-3) 7-6 (7-3) in the first round of the Zagreb Indoors.

In a match that lasted 90 minutes, none of the players had an opportunity to break serve, which probably makes sense.

Karlovic has very little to offer the game, other than his serve and Dimitrov had the frustrating task of trying to return the Karlovic serve, which is virtually impossible.

This is the first time Karlovic has won a match on the ATP Tour since the quarter-final of the Kremlin Cup in Moscow last October.

In other first round action at the Slovakian player Martin Klizan recorded his first match win of 2013. The fifth seed defeated Italian lucky loser Matteo Viola 4-6 7-6(8-6) 6-1 in two hours and 31 minutes, having converted six of his 14 break point opportunities.

Mercurial Czech Lukas Rosol recovered from his record-breaking seven-hour Davis Cup doubles match on Saturday to beat Croatian qualifier Filip Veger 6-2 6-4.

German qualifier Philip Petzschner set a second-round meeting with Italian number two seed Andreas Seppi, who also performed some heroics during the Davis Cup action at the weekend.

Seppi beat Croatian wild card Mate Pavic 7-5 6-2 in 61 minutes. World number 122 Petzschner was a semi-finalist in Zagreb three years ago, which is probably a good omen.

Grega Zemlja beat Serbia's Ilija Bozoljac 6-7(7-5) 7-6(7-4) 6-2 while Blaz Kavic beat countryman Aljaz Bedene 6-7(5-7) 6-3 6-3. The contest between Kavcic and Bedene was the first all-Slovenian match in the main draw of an ATP World Tour event.