World number three Andy Murray clinched a place in the quarter-finals of the Madrid Masters when he dispatched Spanish 16th seed Tommy Robredo 7-5 6-1.
The 21-year-old Scot, who turns 22 on Friday, has never won a tour title on clay and is looking to improve his record on the surface ahead of the French Open which starts later this month.
The Scot wasted eight break points in his opening set before eventually sealing the break 11th game when Robredo produced a forehand error.
The single break of serve was enough to seal a tight first set and three more in the second were enough to seal a comfortable win and the Scot converted his first match point with a backhand return down the line.
He will play either Argentine fifth seed Juan Martin Del Potro or 11th seed Stanislas Wawrinka in the last eight on Friday.
Rafael Nadal, Roger Federer and Novak Djokovic are all seeking places in the quarters on Thursday.
Swiss Federer plays 14th-seeded American James Blake, Djokovic of Serbia takes on unseeded Italian Andreas Seppi and Spaniard Nadal plays Philipp Kohlschreiber of Germany.
World number one Nadal is chasing a sixth title of the season and a fourth on clay while Djokovic is bidding for a fifth consecutive final appearance and a third title of the year. Federer has yet to win an event in 2009.
In other third-round matches on Thursday, sixth seed Andy Roddick plays Nikolay Davydenko, number seven seed Fernando Verdasco meets wild card Juan Monaco and eighth seed Gilles Simon takes on Ivan Ljubicic.