Like some of us said prior to this match, Roger Federer's serve did prove to be the biggest difference in this match.
Roger has never served this big and at key moments for a while now. His serving in the first and fourth set tie-breaks was clutch and couldn't have been timed better.
Novak Djokovic has himself to blame though.
To begin with, his serve was not as good as Rogers', especially in key moments.
Also his movement throughout the match was a shadow of what we have seen in the past six months.
He had several chances to get back in the match, starting with the first set where he had two set points to close out the set, which he didn't convert.
Again, in the fourth, he was serving at 5-4 and could have taken the match to the final set tomorrow. He faltered again, just like he did in the first set when comfortably placed at 4-2 and squandering that lead.
If anyone contends that the mental aspect of the game is not important, they are watching a different sport.
This sport is everything about mental toughness, as was evident today.
Novak Djokovic had just won 43 matches on the trot, and 41 matches this season.
Yet after losing that crucial first set, he was so down on himself mentally that he pretty much conceded that second set. Had he played the second set with more energy and purpose, he could have walked away the winner in this match. He did extend the match, but really after going two sets to down to Federer, he was looking down the barrel.
If Novak wants to win more Grand Slams, he has to lift himself mentally. He too often is down on himself in the midst of matches and it's costing him big time at several key moments in matches.
He needs to look no further than his recent adversary who beat him to end the streak and to whom he lost before this incredible streak started.
Hats off to Roger for his mental toughness and lifting his game when it mattered most. This is a huge win for Roger, probably the biggest of his career.
He can top that if he wins on Sunday, which if it happens, will no doubt be his greatest Grand Slam victory.
PS: John McEnroe might want to send a special bouquet to Fabio Fognini for the walkover, and thus resulting in his record still being intact.