ON and off court, Novak Djokovic has tried to distance himself from Andy Murray.

They have been known to text from time to time, share a bite to eat. They have played football in the same side during charity matches, and spent Saturday huddled over a laptop in the locker room watching Serbia take on Scotland. But as rivals for the greatest prizes in the sport, they will tonight be the best of enemies on Arthur Ashe – using any psychological advantage they can to grind their opponent into the dirt, then speaking warmly of each other in the aftermath.

"I can't be friends with Andy," the Serb has said. "I really like the guy, but how can you go and be best friends with a guy who you know you are going to be doing battle with? It is true for myself, Roger, Rafa and now Andy. There is a mutual respect, but common sense tells you we can't be best friends and hang out all the time."

There is a certain steeliness to the Scot's demeanour this year also, perhaps borne of the wise promptings of Ivan Lendl. As he looked ahead to tonight's final, Djokovic praised Murray and the work of the Czech to the point that he had almost convinced you there was no such thing as a favourite. But the Serb is reigning champion here, and on a 27-match winning run at the hard-court slams.

"He's going for the shots more than he used to," said the Serb. "I don't know if it's with Ivan's help, but he's definitely improved that part of the game. Mentally he is more aggressive. Probably that's the only thing that he was missing. He is one of the most complete players in the world."

Perhaps Djokovic assumed that aggressiveness and assertiveness were his own trademark. His spectacular winning year in 2011 was a marker for all to emulate and – prior to Murray's straight-sets victory in the Olympic semi-final – he had tended to have the whip hand whenever the two met on the big occasions. He won the 2011 Australian Open final in straight sets, he took an epic five-set encounter in this year's semi-final in Melbourne.

"There were a lot of long rallies, and you couldn't really say who was going to win till the last point," said Djokovic. "Most of our matches are very close, with only small margins deciding the winner. We have similar games. We are big rivals and have been in top of the men's game for a long time, so we know each other really well. The last match he won but it was a different surface and with the different surface different tactics apply. So I guess there is no clear favourite."

The 25-year-old Serb was trailing David Ferrer 5-2 when the imminent arrival of a tornado forced the suspension of their semi-final on Saturday. But when the day dawned hot and clear, no-one was surprised that a different Djokovic came out to play. Ferrer is as fit as any player on tour but although he duly served out for the first set, before long the Serb was giving him the runaround. The Spaniard restored parity on serve for a while during the third but was well beaten 2-6, 6-1, 6-4, 6-2. "It was a great relief to get it over with in four sets," Djokovic said.

However long tonight's final takes, there will be no old pals act on show until the winner is known.