BARCELONA (Reuters) - Lleyton Hewitt's comeback from hip surgery stumbled on Spanish clay on Wednesday when the former world number one lost 7-6 6-4 to Eduardo Schwank in the second round of the Barcelona Open.

The 29-year-old Australian, who has played only one tournament since the operation at the end of January, was twice broken by the 59th-ranked Argentine and misses out on a possible last-four clash with French Open runner-up Robin Soderling.

Swede Soderling is the highest-ranked player left in the tournament after a slew of withdrawals, including world number three Rafael Nadal, who has won the Conde de Godo trophy in Barcelona the past five years.

Top 10 pair Jo-Wilfried Tsonga and Fernando Verdasco are in second-round action later on Wednesday.

Tenth-ranked Frenchman Tsonga plays Czech Jan Hajek and number nine Verdasco of Spain, whom Nadal thrashed in the final in Monte Carlo, takes on Tsonga's compatriot Richard Gasquet.

(Writing by Iain Rogers in Madrid, editing by John Mehaffey)