Twice champion Rafael Nadal was gifted a place in the last 16 of the BNP Paribas Open on Monday when Argentina's Leonardo Mayer withdrew before their third-round match with a back injury.
Spaniard Nadal, who beat American Ryan Harrison 7-6 6-2 in the previous round, will next face either Italy's Andreas Seppi or Latvian Ernests Gulbis in the elite ATP Masters 1000 event.
Seeded fifth at Indian Wells where he won the title in 2007 and 2009, left-hander Nadal is competing in his first tournament on a hardcourt surface in almost a year.
The former world number one was sidelined for seven months last year by a lingering left knee injury, and only returned to the ATP circuit last month in South America.
His heavily anticipated comeback went surprisingly well as he won twice after competing in three relatively minor claycourt events, having reached all three finals.