By Nick Georgandis

ATP
Andy Murray's further success on clay and Roger Federer's lack thereof saw the two men flip-flop in the latest ATP rankings on Monday, with Federer now hotly pursued by No. 4 David Ferrer and No. 5 Rafael Nadal.

Murray reached the quarterfinals at the Madrid Masters last week while Federer tumbled in the third round, upset by Japan's Kei Nishikori. Federer won Madrid a year ago, and with 7,760 points is now just 840 points ahead of Ferrer and 865 ahead of Nadal.

This is Murrary's fourth stint at No. 2. He has never attained the No. 1 ranking.

Now just 14-5 on the year, Federer could be in real jeopardy of falling back as far as fifth in the rankings, less than a year after taking over No. 1 by winning Wimbledon. He as a further 1,080 points to defend in the month ahead at Rome and Roland Garros before the tour switches to his favored grass surface, on which he is 117-17 (.873) all-time with 12 titles. Federer has been ranked in the Top 4 every week since July 7, 2003, a span of 514 weeks.

Madrid runner-up Stanislas Wawrinka surged up five spots to join the Top 10 for the first time since October of 2008. The 28-year-old Swiss improved to 25-9 on the year.

Departing the Top 10 was Janko Tipsarevic, off to a shaky 11-10 start to 2013. Tipsarevic had been in the Top 10 since November of 2011.

Despite his upset of Federer, Nishikori could only move up one spot in the rankings to No. 15, passing Canada's Milos Raonic.

American John Isner moved up one spot to No. 20, giving the US two players in the Top 20, albeit the other one being No. 19 Sam Querrey.

Outside of the Top 20, the biggest move was easily that of Spain's Pablo Andujar who rocketed up the charts 59 spots from No. 113 to No. 54 following his trip to the Madrid semifinals which included upset wins of No. 11 Marin Cilic, Isner and Nishikori before falling to Nadal.
To put things in perspective, Andujar accumulated 44% of his season wins (4 of 9) and 57% ($204,716 of $356,758) of his 2013 prize money all came in the past week. Andujar moved within one spot of fellow Spaniard Fernando Verdasco, who fell seven spots after losing in the third round at Madrid.

WTA
In the latest women's rankings, Serena Williams staved off Maria Sharapova's bid to take over No. 1 in the world by beating the Russian in straight sets to win the Madrid Open on Sunday. Williams leads Sharapova by 425 points. Madrid semifinalist Sara Errani jumped up to No. 6 in the world, surpassing Angelique Kerber. Errani is quitely achieving something really rare in the modern tennis world - ranked in the Top 10 in both singles and doubles (she's No. 1 in singles).

Another move in the Top 10 saw Caroline Wozniacki climb to ninth, pushing Samantha Stosur back to 10th. Madrid semifinalist Ana Ivanovic rose three places to No. 13.

It was the first time the former No. 1 has made at least the semifinals of a Masters-level tournament since Indian Wells in 2013.
Still just 25 years old, this is the highest Ivanovic has been ranked since September of 2009.