December 27, 2014: The first official day of partnership and practice between world No. 6 Agnieszka Radwanska and 18-time Grand Slam winner Martina Navratilova.

After announcing their partnership several weeks ago, it appears the two battle-tested competitors are ready to take 2015 by storm.

Navratilova partnership with Aga is the latest in a long line in star coaching roles over the past few years; Andy Murray sparked the trend when he hired Ivan Lendl then Amelie Mauresmo; Novak Djokovic brought Boris Becker on board; Marin Cilic partnered with Goran Ivanisevic to win his maiden Grand Slam title; Roger Federer teamed up with his idol Stefan Edberg, while Kei Nishikori joined forces with Michael Chang.

Photo available on twitter.

Navratilova won 167 WTA titles over the span of her illustrious career, 18 of which were Grand Slam singles titles and won her last Grand Slam mixed doubles title at the US Open in 2006. Her rivalry with Chris Evert goes down as one of the biggest rivalries in women’s tennis, having played each other a total of 80 times, with Navratilova leading the series 43-37.