(CNN) -- Former world number one Rafael Nadal beat James Blake in an entertaining three-setter but newly-crowned U.S. Open champion Juan Martin Del Potro exited the Shanghai Masters on Wednesday.
Top seed Nadal showed signs of returning to his best form against James Blake in Shanghai.
Del Potro went out in the first round of the Tokyo tournament last week to a qualifier and fared little better in China as he trailed Austrian Juergen Melzer 7-5 2-1 before retiring with a wrist injury.
Argentine Del Potro has already qualified for the ATP Tour World Finals in London next month but joins a list of injured players among the world's elite with Andy Roddick retiring from his match in Shanghai on Tuesday and world number three Andy Murrray absent.
Nadal spent four months in the summer sidelined with knee problems, losing his world top ranking to Roger Federer, who is sitting out the Shanghai tournament.
The Spaniard showed signs of returning to his best form against the dangerous Blake, who battled back to level the match on a second set tiebreaker 7-4 after Nadal dominated the opener.
Nadal broke through to lead 4-2 in the decider before sublime play by his American opponent saw him back on level terms.
But the top seed would not be denied and claimed victory with a blistering forehand down the line to wrap up a 6-2 6-7 6-4 second round win.
Second seed Novak Djokovic, who won the Beijing title last week, is also through after wasting little time in the final match of the day to beat Fabio Fognini of Italy 6-3 6-1.
In other action, Sweden's Robin Soderling also went through with a 6-4 7-5 victory over Nicolas Almagro of Spain, but former Shanghai champion Lleyton Hewitt could not progress as he lost in three sets 4-6 6-4 6-2 to 11th seed Gael Monfils of France.
Hewitt led 2-0 in the decider before being swept aside by the unpredictable Monfils, who took the final six games to go through.
Meanwhile, 25-year-old Czech player Ivo Minar has been banned for eight months after testing positive for a banned substance following a Davis Cup match.
A sample taken after the Davis Cup quarterfinal against Argentine on July 11 contained the banned stimulant methylhexanamine, the International Tennis Federation confirmed.