#3 Roger Federer
Despite him not being on top of his game for a larger part of the year, the Swiss Maestro came away with four titles, including one Grand Slam.
He began the year much the same way he did in 2017, winning the Australian Open in January by defeating Marin Cilic in the final. Shortly after that, he went on to win at Rotterdam, which gave him world no. 1 title once again.
However, he did stay no. 1 for too long, as he lost to Juan Marin del Potro in the final at Indian Wells and then suffered a shock defeat to Thanasi Kokkinakis in the first round at Miami, thus giving the world no. 1 ranking back to Nadal.
He was shocked in the quarters at Wimbledon by Kevin Anderson and was upset by John Millman in the fourth round of the US Open as well. However, he went on to win the title at Basel - his 99th overall and played extremely well at the Paris Masters as well.
He ended his season with a defeat to Zverev in the semis of the Tour Finals.
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