Swiss third seed Stanislas Wawrinka, the 2015 French Open champion, was also sent packing when he lost to Uruguay's Pablo Cuevas 6-4 6-4 but nine-time champion Rafael Nadal crushed birthday boy Alexander Zverev for the loss of only two games.
French Open champion Novak Djokovic was made to work hard by Spain's Pablo Carreno Busta, but the Serbian came out on top with a 6-2 4-6 6-4 victory.
Murray was playing only his second match since returning from a five-week layoff after an elbow injury having been handed a first-round bye in the first big European claycourt tournament of the season.
