Novak Djokovic wobbled but avoided joining Rafael Nadal in making an early exit from the BNP Paribas Open.

Stanislas Wawrinka aside, the top men have been finding life rather difficult in the Californian desert, capped by world number one Nadal's shock loss against Alexandr Dolgopolov on Monday evening.

Fourth seed Tomas Berdych lost his first match and Andy Murray scraped through an ugly clash with Jiri Vesely on Monday, while Juan Martin del Potro did not even take to the court because of injury.

Djokovic headed to Indian Wells without a title for the first season since 2006 and question marks remain about his form after a 6-1 3-6 6-1 win over world number 91 Alejandro Gonzalez.

The 25-year-old had never won a main-draw match on the ATP Tour before this week but caused Djokovic plenty of problems.

And the Serb is likely to have to raise his level if he is to make the quarter-finals, with in-form Marin Cilic up next.

The Croatian has blossomed since hiring Goran Ivanisevic as his coach ahead of the start of the season and Tuesday's 6-4 6-3 win over Tommy Robredo was his 20th of the year.

There may be no Nadal any more, but three Spanish men are in the last 16.

Fernando Verdasco was the most impressive on Tuesday, beating eighth seed Richard Gasquet 7-6 (7/5) 6-1 while Berdych's conqueror Roberto Bautista Agut and Feliciano Lopez are also through.