Roger Federer moved up to No. 4 in this week's ATP Tour rankings, his highest position since last June. He trails No. 3 Stanislas Wawrinka by 515 points.
Federer and his replacement at No. 5, Tomas Berdych, both passed David Ferrer, the 2013 Sony Open finalist who fell from fourth to sixth after losing in the fourth round in Miami. The fifth spot equals a career high for Berdych, who reached the semifinals last week before withdrawing with gastroenteritis.
Federer, who lost to Kei Nishikori in the Miami quarterfinals, joins No. 1 Rafael Nadal and No. 2 Novak Djokovic as so-called Big Four members in the actual top four. The fourth, Andy Murray, slipped from sixth to eighth after following up his 2013 Sony Open title with a quarterfinal loss to Djokovic last week. This is Murray's lowest ranking since 2008.
In other rankings news:
• Djokovic has sliced Nadal's lead to 1,560 points after back-to-back titles at the BNP Paribas Open and Sony Open. A month ago, Nadal led the No. 2 by 3,825 points.
• John Isner (No. 9) and Milos Raonic (No. 10) rose one and two spots, respectively, to match their career highs. Raonic displaced Richard Gasquet (now 11th) from the top 10. • Sam Querrey, a second-round loser in Miami, fell from No. 62 to No. 74, his lowest position since June 2012. Bradley Klahn slipped two spots, to No. 65, but replaced Querrey as the No. 2 American behind Isner. Klahn is 1-5 in ATP Tour main-draw matches this year and 3-12 in his career, but he's been successful on the Challenger circuit.