Rome, Italy (SportsNetwork.com) - A trio of seeds, including Bulgarian star Grigor Dimitrov and American John Isner, were among Monday's first-round winners at the $4.335 million Italian Open tennis event.

The 10th-seeded Dimitrov got past 6-foot-8 Pole Jerzy Janowicz 6-3, 7-6 (7-4), while the No. 16 seed Isner erased Portuguese Joao Sousa 7-5, 6-3 on the red clay at the beautiful Foro Italico.

Twelfth-seeded Frenchman Gilles Simon moved on by overcoming rising American Jack Sock 4-6, 7-6 (7-2), 6-3 on Day 2.

"I had a tough time finding my game," Simon said. "If I play like that again I'll be out."

Simon was impressed with Sock's ability.

"He serves like (Andy) Roddick and his forehand is like (Rafael) Nadal's," Simon said. "If he works on his other shots he could improve a lot."

Elsewhere in the first round, Italian favorite Fabio Fognini subdued American Steve Johnson 7-6 (7-0), 6-3; Frenchman Richard Gasquet bested Italian qualifier Thomas Fabbiano 6-1, 7-6 (7-0); Turkish qualifier Marsel Ilhan topped France's Adrian Mannarino 6-4, 6-1; German Philipp Kohlschreiber grounded American Donald Young 6-4, 6-1; Argentine Juan Monaco slipped past Serbian qualifier Dusan Lajovic 6-3, 6-7 (5-7), 6-2; Uruguay's Pablo Cuevas pasted Italian Paolo Lorenzi 6-3, 6-2; and Austrian Dominic Thiem defeated Italy's own Simone Bolelli 7-6 (7-4), 7-6 (7-5). Cuevas will meet Roger Federer in his next outing in a rematch of the recent Istanbul final, which was won by the Swiss great. Federer is a three-time Rome runner-up.

Novak Djokovic beat then reigning two-time champion Rafael Nadal in last year's marquee Rome finale. Nadal is a seven-time titlist here, while Djokovic owns three championships in the "Eternal City."

The two greats have combined to win the last 10 titles at this Masters 1000 tournament.

The high-flying Djokovic will open his week against Spaniard Nicolas Almagro on Tuesday, while Nadal will face Ilhan in the round of 32 on Wednesday.

The Australian Open and Wimbledon champion Djokovic already owns three Masters titles this season.