Second seed Roger Federer saw off the challenge from French Gilles Simon 6-1, 6-2 to continue his pursuit of a maiden final in 2013. He will now play Jerzy Janowicz, who beat Richard Gasquet 3-6, 7-6(2), 6-4 Thursday, Xinhua reports.
World no.1 Djokovic dispatched Ukrainian Alexandr Dolgopolov 6-1, 6-4.
The 2008 and 2011 winner used 60 minutes to wrap up the win and will next play sixth seed Tomas Berdych, who extended his perfect record to 8-0 against Kevin Anderson in a 7-5, 6-2 win in 84 minutes.
Djokovic ran through the first set in 29 minutes, losing just two of his 17 first service points, and got off to a good start in second. He met some serious challenge in the sixth game having to save two break points before ultimately securing victory.
Berdych hit 25 winners to book his place in the quarter-finals for the fourth time.
Six-time champion Rafael Nadal overcame a fierce challenge from Latvian qualifier Ernests Gulbis and reached the quarter-finals with a 1-6, 7-5, 6-4 win.
The fifth seed will next face fourth-seeded David Ferrer, who advanced when Philipp Kohlschreiber of Germany withdrew because of dizziness.
The only men's seed to lose was No.7 Juan Martin del Potro, who was beaten by 36th-ranked Benoit Paire of France 4-6, 6-7 (3).
In the women's draw, world No.1 Serena Williams routed 14th-seeded Dominika Cibulkova 6-0, 6-1 for her 21st consecutive win, matching the best streak of her career.
As local hope Sara Errani of Italy was playing in the main stadium, Williams was arranged to play on an outer court. She didn't make the appearance last too long, winning in 61 minutes.
The second seed Maria Sharapova also won easily. She beat 16th-seeded Sloane Stephens 6-2, 6-1.
Third-seeded Victoria Azarenka was up 6-1, 2-0 when Ayumi Morita retired. Azarenka won 70 percent of the points in the match when play stopped.
The top three seeds were joined in the quarter-finals by two-time champion Jelena Jankovic, who edged fifth-seeded Li Na of China, 7-6 (2), 7-5
The last remaining Italian in the tournament is Errani, who advanced when 12th-seeded Maria Kirilenko of Russia retired while trailing 3-6, 0-2 with a left knee injury.
--IANS (Posted on 17-05-2013)