Tomas Berdych had to come from a set down to beat qualifier Andrey Kuznetsov in the first round of the Monte Carlo Masters on Monday.
Berdych spurned match points against Roger Federer in the Miami Open quarter-finals and was unconvincing as he claimed a 4-6 6-3 6-4 win over Kuznetsov.
Along with ninth seed Berdych, 12th and 13th seeds Roberto Bautista Agut and Pablo Carreno Busta both needed three sets to progress to the second round.
But there were no such struggles for 14th seed Alexander Zverev, the promising German coming through in straight sets against Andreas Seppi.
BERDYCH SURVIVES KUZNETSOV SCARE
Berdych appeared set for a stunning defeat after he lost the first set and faced break points at 2-2 in the second.
But he survived a mammoth service game to hold and subsequently forced a decider.
The Czech struck the crucial break in the third game of the final set, and that proved enough for him to avoid what would have been a first-round exit for the second year running in Monte Carlo.
ZVEREV ENJOYING THE CLAY
Zverev has already enjoyed a productive year, winning the Open de Sud de France and reaching the quarter-finals in Miami.
And the 19-year-old needed only 68 minutes to see off wildcard Seppi, who enjoyed the support of the crowd in Monaco.
Speaking after the win, Zverev said: "I like playing on clay. It's the surface I grew up on. In Europe, you play most of the season on clay.
"I actually don't know what my favourite surface is, and I don't actually have a least favourite surface. It more depends on how I play during the time. It more depends on which form I'm in, more than the surface."
SPANISH QUARTET INTO SECOND ROUND
Nikoloz Basilashvili easily claimed the first set against Bautista Agut, but the Georgian could not complete a shock victory, slumping to a 1-6 6-3 7-5 defeat.
Carreno Busta joins compatriot Bautista Agut in the next round after a 7-6 (7-0) 6-7 (4-7) 6-3 victory over Fabio Fognini.
Fellow Spaniards Albert Ramos-Vinolas and Nicolas Almagro overcame Renzo Olivo and Martin Klizan respectively, but Guillermo Garcia-Lopez lost to Adrian Mannarino.
Pablo Cuevas eased past Viktor Troicki 6-3 6-0, Kyle Edmund won an all-British battle with Dan Evans and Diego Schwartzman knocked out Bernard Tomic.