Andy Murray is only 24 but there are many who believe his time could be running out while some reckon his best is behind him.
Murray needs to stand up and deliver soon
After losing two consecutive Australian Open finals and the 2008 US Open earlier, Andy Murray seems to be finding himself at the centre of the same debate as Caroline Wozniacki.
The Scot is only 24, but there are many who believe his time could be running out. Others reckon his best is behind him - the summer of 2009, when he peaked at No 2, winning Queen's Club and the Rogers Cup, and reaching the semi-finals at Wimbledon and Cincinnati.
His straight sets rout by Kevin Anderson in Montreal last week has added to the debate, as Murray became the first reigning Rogers Cup champion to exit in his first match since Marat Safin in 2001.
Worryingly, this was not his first inexplicable defeat this season. At Miami in March, he was bounced out by Alex Bogomolov, and he lost to Donald Young a couple of weeks earlier. He has lost his five games to the top three this year - Novak Djokovic, Rafael Nadal and Roger Federer - and has not won a single set in those matches.
Federer had tipped Murray to get a grand slam title before Djokovic; the Serb has now won three, and is No 1 after a year during which he has lost just once in 54 matches.
Can Murray, the world No 4, then be considered a part of the men's elite, alongside Djokovic, Nadal and Federer? With Jo-Wilfried Tsonga and Gael Monfils making rapid strides, the Scot needs to take steps like Djokovic.