DEFENDING champion Andy Murray eased into the fourth round of the Sony Open in Miami with a straight-sets win over Spain's Feliciano Lopez.
Murray extended his perfect record against Lopez to 9-0 with a 6-4, 6-1 victory in 73 minutes to set up a clash with France's Jo-Wilfried Tsonga, who recovered from 5-1 down in a second set tie-break to beat Marcos Baghdatis in three sets.
World number six Murray made the ideal start with a break of serve to love in the opening game of the match, but there was a moment of concern in the next game when he grabbed his lower back in pain after dumping a forehand into the net.
The Scot lost that game after saving two break points, but did not appear to be hampered afterwards and he soon broke Lopez again for a 3-2 lead.
Murray lost just one point in each of his next three service games to serve out the set and again broke Lopez at the start of the second set.
Lopez looked to be suffering from back problems of his own and never threatened to get back into the contest, losing his serve twice more as Murray sealed victory with a casual backhand return winner down the line.
"I moved well (and) returned well," said Murray. "It's not always that easy to feel comfortable against him because there is not (a lot) of rhythm with the way he plays."
Roger Federer served up another comfortable victory, beating qualifier Thiemo de Bakker in straight sets.
The fifth seed and two-time former champion lost just seven points on his serve as he ran out a 6-3 6-3 winner in 63 minutes, setting up a clash with France's Richard Gasquet in the fourth round.