Beijing - World No 2 Novak Djokovic enjoyed a convincing straight-sets win against unseeded journeyman Carlos Berlocq of Argentina on Wednesday to progress to the quarter-finals of the China Open.
The 25-year-old Serbian maintained his unbeaten record at the Beijing tournament by dismantling the player ranked 50th in the ATP standings 6-1, 6-3.
Djokovic won the first set in only 25 minutes and raced to a 5-0 lead in the second, only to lose three games carelessly before wrapping up the match.
The former world No 1 has won the event on the two occasions he has entered, in 2009 and 2010, but missed last year because of injury.
The No 1 seed will play Austrian Jurgen Melzer in the next round. Melzer knocked out sixth seed Alexandr Dolgopolov in three sets.
In the women's draw world No 2 Maria Sharapova made light work of her second-round match, progressing to the last 16 with ease.
The Russian No 2 seed defeated Romania's Sorana Cirstea, ranked 29th in the WTA standings, in straight sets, 6-2, 6-2.
"I thought I served really well today, much better than the first round," the winner of four Grand Slam singles titles said.
"She (Cirstea) is someone that likes to be aggressive, get the first shot and hit it really hard. I was happy I took her time away. It was important to try to take that away from her," Sharapova added.
The 25-year-old will face Slovenia's Polona Hercog, 90th in the rankings, in the third round.
There was a shock in the last 16 when the 69th-ranked Romina Oprandi of Switzerland beat former world number one Ana Ivanovic in straight sets to progress to the quarter-finals.
Oprandi, who received a late entry after Serena Williams withdrew just two days before the start of the tournament, defeated the eleventh seed from Serbia 6-4, 6-3.
"I really struggled to find my rhythm out there today, especially on the forehand," the world-number-12 Ivanovic said.
"The ball was coming without much pace and I wasn't really efficient moving forward and taking advantage of that," she added. "It was the unforced errors that made a big difference."
Ivanovic's compatriot Jelena Jankovic was also knocked out, losing to Spain's Carla Suarez Navarro 7-5, 6-4.
Navarro will play France's Marion Bartoli in the quarter-finals after the ninth seed overcame Julia Goerges of Germany 6-3, 7-6 (7/2).
Results from the China Open in Beijing on Wednesday (x denotes seeding):
Jurgen Melzer (AUT) bt Alexandr Dolgopolov (UKR x6) 7-6 (11/9), 2-6, 6-1
Florian Mayer (GER) bt Marius Copil (ROM) 3-6, 6-3, 6-2
Novak Djokovic (SRB x1) bt Carlos Berlocq (ARG) 6-1, 6-3
Maria Sharapova (RUS x2) bt Sorana Cirstea (ROM) 6-2, 6-2
Polona Hercog (SLO) bt Ekaterina Makarova (RUS) 7-6 (7/5), 3-6, 7-6 (7/3)
Romina Oprandi (SUI) bt Ana Ivanovic (SRB x11) 6-4, 6-3
Carla Suarez Navarro (ESP) bt Jelena Jankovic (SRB) 7-5, 6-4
Marion Bartoli (FRA x9) bt Julia Goerges (GER) 6-3, 7-6 (7/2)