World No 2 Rafa Nadal sailed into the quarterfinals of the China Open, his first tournament in 13 weeks, with a 6-3 6-4 win over German qualifier Peter Gojowczyk on Thursday.
The Spaniard, returning from a wrist injury, won 85 percent of his first service points against the German and took an hour and 45 minutes to seal victory and set up a last eight clash with Martin Klizan at the ATP 500 event.
Slovak Klizan was leading 6-2 3-0 when seventh seed Ernests Gulbis retired due to a right shoulder injury.
Third seed Tomas Berdych moved up a place to seventh in the race to the season-ending ATP World Tour Finals in London after his 6-3 6-4 victory against wild card Viktor Troicki despite a poor serving display.
The Czech only managed to make 32 percent of his first serves and now meets eighth seed and big server John Isner in the quarterfinals.
Elsewhere on Beijing's blue hard courts, Bulgarian Grigor Dimitrov beat Spaniard Pablo Andujar 6-4 6-4 to set up a quarterfinal clash with world No 1 Novak Djokovic, while sixth seed Andy Murray beat Pablo Cuevas 6-2 6-2.
In the women section, Russian Svetlana Kuznetsova upset seventh seed Angelique Kerber in three sets, while Petra Kvitova also reached the quarterfinals without hitting a ball after American Venus Williams withdrew with a viral illness.
Twice champion Kuznetsova dropped the first set but eventually prevailed 2-6 6-4 6-3 in the two-hour-and-eight minute battle that complicates her German opponent's hopes of qualifying for the season-ending WTA Finals in Singapore.
Kerber is ninth in the race for next month's event featuring the top eight players and could have improved her position with a better showing in China.
Second seed Simona Halep, one of the four players to have already secured a place in the Singapore event, battled past Andrea Petkovic of Germany with tie-breaks separating the pair in two of the three low quality sets.
The Romanian, who produced 91 errors, fought for more than two and half hours to tame Petkovic 7-6(4) 5-7 7-6(1) and reach the last eight where she will meet Ana Ivanovic, who downed Sabine Lisicki 6-3 7-5.
Italian Roberta Vinci prevailed in a three-setter, upstaging 12th seed Ekaterina Makarova 6-1 0-6 7-5.