German Michael Berrer posted a first-round upset at the pbz zagreb indoors, ousting No. 5 seed Janko Tipsarevic of Serbia 7-6(5), 6-3 Tuesday at the ATP World Tour 250 indoor hard-court tennis tournament.

The 65th-ranked Berrer, who had come into Zagreb straight from his title win at the ATP Challenger tournament in Heilbronn, capitalised on three of his 11 break point opportunities against the 2008 Zagreb quarter-finalist to close out the win in one hour and 55 minutes.

Berrer will attempt to reach an ATP World Tour quarter-final for the second time in 2010 when he next faces Croatian wild card Petar Jelenic. The 22-year-old Split native, currently ranked No. 544, earned his first tour-level win as he defeated Serbian qualifier Ilija Bozoljac 7-6(6), 7-5.

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ATP World Tour No. 41 Benjamin Becker overcame a tough test on his Zagreb debut, rallying from a set down to edge Swedish qualifier Andreas Vinciguerra 1-6, 6-1, 7-6(4). The 28-year-old Becker, who was narrowly defeated by Nicolas Almagro in five sets in the second round of the Australian Open, improved to a 4-3 mark on the season.

The 28-year-old Becker, who was narrowly defeated by Nicolas Almagro in five sets in the second round of the Australian Open, improved to a 4-3 mark on the season.

The sixth seed suffered a poor start in his first meeting with Vinciguerra, dropping the first five games as the Swede raced to a one-set lead. Becker quickly reversed his fortunes, though, by breaking serve twice as he levelled the match with a 6-1 second-set score line. In a third set featuring no service breaks, the German then edged the deciding tie-break after one hour and 45 minutes.

Becker next will face fellow German Philipp Petzschner, who fired 21 aces and broke serve five times from 13 opportunities as he defeated Belgian Christophe Rochus 6-7(4), 6-3, 6-1 in just over two hours. Victory marked World No. 84 Petzschner’s first match win of the season, with the right hander having suffered first-round losses at the Brisbane International (l. to Gicquel) and the Australian Open (l. to Mayer), where he let slip a two-set lead.

Slovakian Lukas Lacko was granted a place in the second round when Uzbekistan’s Denis Istomin was forced to retire due to a right hamstring injury, with Lacko leading 6-2, 2-2. The 22-year-old Lacko, this week a career-high No. 72 in the South African Airways 2010 ATP Rankings, improved to a 4-2 mark on the season and next could meet 2006 champion, Ivan Ljubicic, should the No. 2 seed defeat Arnaud Clement.

In other first-round matches Tuesday, Austrian Daniel Koellerer edged past Kazakhstan’s Andrey Golubev 6-3, 3-6, 6-3 and Frenchman Alexandre Sidorenko beat fellow qualifier Ruben Bemelmans of Belgium 7-6(5), 3-6, 6-3.