Monte Carlos - Andy Murray struggled to survive his opening match of the season on clay, with the second seed scratching out a narrow 6-2, 4-6, 6-3 win over French qualifier Pierre-Hugues Herbert at the Monte Carlo Masters on Tuesday.
Murray needed two hours to book his place in the third round after losing serve four times against Herbert.
"I knew it would be a tough match," the two-time semi-finalist said. "I just managed to turn it around at the end.
"It was a tight third set, he had chances to break me. I had to hang tough: This was a good one to get through."
Third seed Roger Federer was making his return to tennis two and a half months after knee surgery, with the Swiss third seed beginning his pre-Roland Garros clay campaign against Spaniard Guillermo Garcia-Lopez.
Federer has never won the Monte Carlo title, losing in four finals, most recently in 2014 to compatriot Stan Wawrinka, the reigning French Open champion.
Murray has yet to regain his top form two months after becoming a father.
The 28-year-old has a massive set of clay-court ranking points to defend after last year winning his first two titles on the surface at Munich and Madrid.
Murray improved his tournament record to 12-7 with the victory. He needed battle in a tight third set against the 95th-ranked Herbert, breaking to love for a 3-1 lead that proved decisive.
Spain's injured seventh seed David Ferrer withdrew a day prior to his second-round match against German teenager Alexander Zverev. He was replaced by compatriot Marcel Granollers.
Ferrer, a finalist in the Principality five years ago against Rafael Nadal, has had a patchy 2016 season, taking a break from late February to late March to rest.
Upon his return, the ATP number eight lost in the Miami third round to France's Lucas Pouille.
Frenchman Gilles Simon also earned a second-rond win, beating Bulgarian Grigor Dimitrov 6-4, 6-3.
In the first round, Portugal's Joao Sousa beat Ivo Karlovic 6-3, 7-6 (7/4), Bosnian Damir Dzumhur put out Robin Haase 6-2, 6-0 and Pablo Cuevas needed three hours 20 minutes to defeat Daniel Gimeno-Traver 7-6 (7/2), 6-7 (2/7), 7-6 (7/4).