Between 2005 and 2014, Rafael Nadal claimed at least one Major title for ten straight seasons, setting a record that will hardly get broken. Struggling with injuries, the Spaniard played only seven matches after Wimbledon 2014 and lost momentum ahead of the new season.
Nadal reached the quarter-final at the Australian Open and Indian Wells in 2015, backed by a small ATP title on clay at the beginning of March. Andy Murray dethroned Nadal in Madrid, and he experienced only the second Roland Garros loss to Novak Djokovic in the quarters.
Rafa barely stayed in the top-10 in the next couple of months thanks to winning trophies in Stuttgart and Hamburg, doing his best to find the winning form but struggling again in Montreal, Cincinnati and the US Open. Nadal toppled Sergiy Stakhovsky and Mikhail Youzhny to advance into the last eight in Montreal, facing the 4th seed Kei Nishikori.
It was their eighth meeting and the first victory for the Japanese, who ousted the Spaniard 6-2, 6-4 in an hour and 23 minutes to reach the semis. Kei's first serve proved to be the most potent weapon of the day, and he fended off two out of three break chances to mount the pressure on the other side.
Rafa hit six double faults and could not do much behind the initial shot, getting broken four times from as many chances offered to Kei and slamming the exit door.
Rafael Nadal lost to Kei Nishikori in straight sets in Canada 2015.
Nishikori landed two great winners in the second game to get his name on the scoreboard and grabbed a break a few minutes later for an early lead.
Firing from all cylinders, Kei secured another break in game five and clinched the opener with another forehand winner at 5-2. Nadal hit a double fault at 1-1 in set number two to experience a break and find himself 6-2, 3-1 down.
Racing towards the finish line, Nishikori placed a return winner to earn another break and extend the gap in game five before Nadal pulled one break back to remain in contention. Rafa held at 15 in game nine with a forehand crosscourt winner, and Kei painted a forehand winner in the next one to seal the deal and beat Rafa for the first time.
It was Nadal's first season since 2004 without the Masters 1000 title by the time of the Canada Masters, and it would not get better in the season, despite a solid effort in Shanghai and Paris.