(Agencies)
Updated: 2008-05-09 10:36

ROME - World number one Roger Federer beat Croatia's Ivo Karlovic 7-6 6-3 in the Rome Masters on Thursday to book a quarter-final against Czech Radek Stepanek.

Swiss Roger Federer returns a backhand to Croatian Ivo Karlovic during their ATP Tennis Open tird-round match in Rome. Federer won 7-6, 6-3. [Agencies]

Earlier, Australian Open champion Novak Djokovic edged past Russia's Igor Andreev 6-3 3-6 6-3 in his third round match and will face Spain's Nicolas Almagro in the last eight.

Russian fourth seed Nikolay Davydenko fell by the wayside after he was edged out 4-6 6-2 7-6 by Spain's Tommy Robredo.

Top seed Federer's fluid tennis met stubborn resistance from Karlovic in the first set. The Croat, aided by some brutal serves, saved four break points in the eighth game and a set point in the 12th before losing the tiebreak.

Federer then drilled a forehand on to the line to clinch the third of three break points in the fifth game of the second and broke again in the final game to cruise home.

The Swiss player admitted that the towering Croat's big serves were hard to handle initially.

"It's completely different to any other serve out there because of his size and he backs it up well at the net," he told a news conference. "He puts a lot of pressure on you because he can hit all four corners very easily.

"But I think I did well in the second set. I created many opportunities, many more than he did, and that's why I started to relax as the game went on."

Third seed Djokovic had to work much harder than Federer.

After an early exchange of breaks, the 20-year-old Serb took Andreev's serve in the fourth game with impressive returns and wrapped up the set with a beautifully executed volley.

But the Russian had no intention of lying down in their third round match and pulled back into contention by taking the second set having broken in the fourth game.

LEG INJURY

Djokovic looked rattled for a spell and came close to losing his serve again three times before regaining his composure to break in the second game of the final set.

Serbia's world number three had to dig himself out of more trouble in the seventh game of the decider before serving out the match.

Davydenko hauled himself level from two breaks down in the final set against 14th seed Robredo and then recovered another dropped service game before losing the match in a tiebreak.

Robredo will face top American Andy Roddick, who took out the last Italian with a 7-6 6-3 victory over Simone Bolelli, a surprise finalist in Munich last weekend.

Stepanek set up a match against Federer by ending Peruvian qualifier Luis Horna's impressive run with a 6-4 1-6 6-3 win.

Almagro reached the last eight when Chilean Fernando Gonzalez, last year's finalist, pulled out of their match with a leg injury.

Juan Carlos Ferrero failed to build on Wednesday's shock win over fellow Spaniard Rafael Nadal and was beaten 6-4 6-3 by Switzerland's Stanislas Wawrinka.

Wawrinka will be pitched against American eighth seed James Blake, who rallied to beat Spain's Fernando Verdasco 5-7 7-5 6-2.