Zagreb, Croatia (SportsNetwork.com) - Former champion Sergiy Stakhovsky was among Monday's first-round winners at the Zagreb Indoors tennis event.

The 2008 winner from Ukraine handled promising Croatian teenager Borna Coric 6-2, 6-4, while another result saw Lithuanian Ricardas Berankis vanquish Slovak and 2012 runner-up Lukas Lacko 6-0, 6-2 at Dom Sportova.

Two-time reigning champion and four-time overall titlist Marin Cilic of Croatia is unable to defend his titles this week due to a shoulder injury.

This week's top seeds are towering Croatian favorite Ivo Karlovic and Frenchman Adrian Mannarino.

The 2015 Zagreb champion will collect $90,000.