Andy Murray's win at the Rogers Cup in Toronto dispels any doubts people may have had as to his ability to perform without a coach in his corner.
It was the best I have seen the Brit play since the Australian Open, and he looked utterly sensational in winning the tournament and beating both Roger Federer and Rafael Nadal along the way.
What the victory showed quite clearly is that Murray does not require a coach in the conventional sense, but rather a mate.
If there is an outstanding coach available who the Brit feels entirely at ease with, then that is all well and good, but otherwise he should keep his friends close to him.
The last thing that Murray needs is a coach to come in with his own ideas to upset his development - he is better off keeping things just the way they are at present.
An assistant is sometimes required to provide affirmation and reassurance, but he had the perfect balance of defence and attack in Toronto and nothing drastic needs to be changed.
Murray's win over Nadal was the one which was the most impressive, and the Spaniard gave it everything but was simply not good enough to match him.
The balance of Murray's game was sublime, and he was able to up his intensity at all the key moments in the match to ensure that he remained in control.
The Brit is comfortably as good as Nadal and Federer right now and has the ability to clinch his first Grand Slam title at Flushing Meadows.
Of course, the record does not lie and Murray has been unable so far in his career to beat Nadal and Federer when it really matters to break his duck.
But something has got to change and, in pure tennis terms, he has the talent and the mental strength to beat the pair and go all the way.
Perhaps it is fair to say that Federer would not have played nearly as aggressively in a Grand Slam as he did in Toronto, and maybe the focus was not there.
Murray was switched on and very focused at the Rogers Cup and, if he can take that same discipline and mental approach into the US Open then he has every chance.
On his day, Murray is every bit as threatening as Nadal and Federer and if he channels his energy correctly then I think one Grand Slam win could lead to many more.