Murray is already out of the singles in Barcelona
Andy Murray hit back from his opening-round singles exit in Barcelona by advancing in the doubles on Wednesday - but brother Jamie went out.
Andy and partner Ross Hutchins edged out Robert Lindstedt and Thomas Johansson 6-4 2-6 (10-3).
But Jamie and Max Mirnyi, seeded eighth, slumped to a 6-4 6-2 defeat by Feliciano Lopez and Fernando Verdasco.
Reigning singles champion Rafael Nadal began his title defence with a 6-4 6-2 defeat of Italian Potito Starace.
Nadal, who beat Roger Federer to win his fourth straight Monte Carlo Masters title on Sunday, overcame Starace in 78 minutes with four breaks of serve.
The world number two from Spain has now won 99 out of his last 100 clay matches since claiming his first Monte Carlo title in 2005.
He will now meet fellow Spaniard and regular doubles partner Feliciano Lopez, who advanced after a tough battle with wild-card Alberto Martin - also from Spain.
Lopez recovered from the loss of the first set to prevail 3-6 6-2 6-4.
Elsewhere, second seed David Ferrer opened his bid for the title with a convincing win over Gabriel Trujillo Soler.
World number five Ferrer was in commanding form, dropping just two games in his 6-1 6-1, 50-minute encounter, and plays Ecuador's Nicolas Lapentti next for a quarter-finals berth.