Swiss player Stan Wawrinka sprung a surprise on Novak Djokovic on Sunday, pulling away from the world's best tennis player in a way Andy Murray can only dream of, and winning the US Open, the third Grand Slam of his career.
So what does this mean? Does Murray have a new rival to think about?
1. Grand Slams
Murray's pursuit of Grand Slam titles has defined his career. The Scot finally managed a win against Djokovic at the 2012 US Open, with a maiden Wimbledon title swiftly following. But while he recently added a second Wimbledon title to that record, Murray has struggled to add to his tally on a regular basis.
Stan Wawrinka also has three Grand Slam titles now, and in an era when Murray was supposed to be left to battle it out with Djokovic, that will irritate the British number one. Furthermore, Stan is just one title away from the career Grand Slam, missing just a Wimbledon title, while Murray is missing both the Australian and French Open.
2. Major Finals
Probably another sore point for Murray, this: having lost four Grand Slam finals before finally winning one, Andy has gone on to lose four more since, all against Djokovic. Meanwhile, Wawrinka has won all of his Grand Slam finals without a single loss, with all three coming in the last three seasons.
The fact that Murray has reached 11 finals obviously puts him in a different category altogether, but oh how he'd love to have Stan's 100% record at the final hurdle.
3. Head to Head
When the two players do meet, it's quite a contrast in styles. Murray's defence is one of the greatest in the world, while Wawrinka's shot-making is elegant in a way that Murray cannot match.
The Scotsman leads 9-7 overall and 3-2 in Grand Slams, but of the last four matches between the pair, Murray has won only once. Furthermore, those three losses have all been on the hard court, which is supposed to be one of the British number one's favoured surfaces.
4. Alternative Record
Both players have also achieved great things for their countries, but who comes out on top? Well, it's close, but Murray edges it. The Wimbledon champion has won two Olympic gold medals in the men's singles, beating Roger Federer in 2012 and Juan Martin Del Potro at Rio 2016, as well as winning silver with Laura Robson in the mixed doubles in London. Murray has also won the Davis Cup with Great Britain, in 2015.
Wawrinka, however, also boasts a Davis Cup title, which he won with Switzerland in 2014, as well as an Olympic gold medal, earned at the Beijing Olympics in 2008. It came in the doubles with Roger Federer, but doesn't quite match up to Andy's haul.
5. Career Titles, Earnings, and Ranking
Murray holds the upper hand across the board in this category. He sits at number two in the world, while Wawrinka is currently at a career-high number three. Murray also leads Stan 39-15 in career titles, and has earned almost double the prize money, at roughly $50 million to Stan's $26 million.
Murray clearly has enjoyed a more consistently impressive career than Wawrinka, but while the two are tied 3-3 in Grand Slams, that won't be of much comfort.