Roger Federer reached the fourth round of the Sony Ericsson Open in Miami, but was made to sweat by Frenchman Florent Serra.
The top seed won 7-6 (7/2) 7-6 (7/3) in one hour 32 minutes to set up a meeting with Tomas Berdych of the Czech Republic.
The Swiss star dropped his serve three times, but converted three of the eight break-point chances he had, including two in the second set, and held his serve when it counted.
Serra was let down by his first serve, making just 49%, but Federer will also look to improve on his mark of 58% in the next round.
Berdych, the 16th seed, was a 6-4 7-5 winner over Horacio Zeballos of Argentina.
A single break gave Berdych the first set and two more followed in the second, Zeballos claiming one of his own.
American Mardy Fish, Andy Murray’s conqueror, claimed another scalp with a 7-5 6-3 win over 29th seed Feliciano Lopez.
Fish carved out 13 break points, converting just two, but saved the two he faced to claim victory.