Updated

Rising Japanese star Kei Nishikori highlighted Monday's opening-round winners, as the 2013 ATP World Tour season kicked off at the Brisbane International tennis event.

The fifth-seeded Nishikori, who turned 23 on Saturday, handled top Aussie Marinko Matosevic 7-5, 6-2 on the hardcourts at Queensland Tennis Centre.

Also on Day 1, sixth-seeded German Florian Mayer topped Colombian Santiago Giraldo 6-4, 6-4, Cypriot Marcos Baghdatis beat Aussie wild card Benjamin Mitchell 6-4, 6-4, and Finnish veteran Jarkko Nieminen held off Frenchman Julien Benneteau 6-3, 2-6, 6-1. Nieminen was a finalist here in 2008.

On Tuesday, wild card and Aussie hero Lleyton Hewitt will meet Czech veteran Radek Stepanek, the 2009 Brisbane titlist and 2010 runner-up.

This tournament serves as a tune-up for the Australian Open, which will commence January 14. U.S. Open and Olympic champion Andy Murray beat Ukrainian Alexandr Dolgopolov in last year's finale. Murray is this week's top seed.