Andy Murray will draw on the memories of the two biggest days of his career when he takes on Novak Djokovic for a place in the semi-finals of the US Open.

Wednesday's match will be the earliest ever meeting at a grand slam for the two former junior rivals, who were born just a week apart and rose through the ranks together.

With Murray only seeded eighth following his drop down the rankings, the danger was that he would come up against Djokovic or Roger Federer in the quarter-finals, and so it has proved.

Djokovic leads the overall head-to-head 12-8 and won their only previous match this season in Miami in straight sets.

But their last three clashes at slams all came in finals, and Murray won two of them - the five-set epic in New York in 2012 that finally broke his grand slam duck and then last summer's emotional Wimbledon victory.

"They obviously will help," said Murray. "I wouldn't say in terms of getting confidence, it's just having that experience of playing those matches.

"They were both very long, tough matches, as well. So I know that I can last those matches against him. But anything can happen in a couple of days. I'll just do everything properly and hope on Wednesday I play a good match."

Murray played his best match of the season in the fourth round to beat Jo-Wilfried Tsonga - his first top-10 scalp since the Wimbledon final.

He feels he is not far away from hitting top form for the first time since back surgery last September but also knows he has had worrying let-downs in big matches this season.

In the French Open semi-finals he suffered his worst ever grand slam defeat against Rafael Nadal.

That could be at least partly explained by the gruelling path he had taken to get there but at Wimbledon he looked in prime form only to surrender meekly to Grigor Dimitrov in the quarter-finals.

He enjoys playing Djokovic and, barring a few of their early matches, usually plays very well against the Serbian, who has very similar strengths to Murray.

The match is likely to be played under the lights on Arthur Ashe Stadium, a stage Murray loves, and he will try to relish the occasion.

He said: "I think that's really why we play the game. That's what you put the work in for, so that when you come to these events and you do have to play against the best players, you're ready.

"And as much as it's incredibly tough and challenging, that's what you enjoy. Playing on Wednesday night against the number one player in the world is exciting.

"If you aren't getting motivated or pumped for those matches, then that's when there's a problem and it's time to maybe stop."

Djokovic came into the tournament with doubts over his form but has looked the most impressive player so far and is yet to drop a set.

Although Murray has not reached a final in any tournament this season, Djokovic is expecting his old rival to bring his best form on Wednesday.

"We all know his quality," said the Wimbledon champion.

"He knows how to play on centre court at the US Open where he has played some great tennis and we've had some great matches. It's a very tough draw. I'm going to have to be playing my highest level in order to advance.

"I think he performs his best in the grand slams. He's been on and off this year but I think in the big matches, as the tournament progresses, he's still fit. He still plays very high-quality tennis. That's what I expect him to do."

Djokovic buried his own demons by beating Federer to win Wimbledon, ending a run of three straight losses in slam finals.

The Serbian is looking to make it five successive finals at Flushing Meadows but he has only won one, in 2011, with Murray beating him once and Nadal twice.

Djokovic said: "In 2011, I played great tennis throughout the whole tournament. In 2012 it was the same but I didn't manage to make that final step.

"As we come closer and closer to the finish line, the matches will get tougher, so that's where I will see where my game is and if I'm mentally strong enough to hold on.

"I have had a great Wimbledon run, Roland Garros, a great clay-court season. So I want to continue on. I want to build on that. I feel good about my game, myself.

"My physical state is pretty good. I'm fit. This is something that is obviously encouraging me for the next one."