Andy Murray ran into the 'one-man army' that is Novak Djokovic at the French Open

We all know what it's like to have an off day. Or a dodgy 10 minutes. A period when we fall below our usual standards and make a mistake or two. It's part of being human. Or so we like to think.

Perhaps the thing about great champions is that they don't do off days. They maintain standards. They have a baseline of excellence and seldom fall below it. Perhaps one of the ways we define champions is as people who have fewer off days than the rest of us.

They don't just have higher peaks; they have fewer if any troughs. And such troughs as they have are still of a dizzyingly high altitude. Certainly that's the conclusion to draw from watching Novak Djokovic at the French Open in Paris this week. Today he spent his lunch hour snuffing out the challenge of Andy Murray. And Murray was brilliant. Intermittently.

The story of the match is that unrelenting excellence beat intermittent brilliance. Murray's best was better than anything Djokovic managed in the course of this five-set match played over two days. The problem was that Murray's worst was way below the lowest of Djokovic's troughs.

The match stopped last night in the middle of Murray's frenzied resurgence. It finished today with Djokovic in full control. He won 6-3, 6-3, 5-7, 5-7, 6-1 -- and at his best he was so good that he scrambled the mind of his opponent. It wasn't the level he was able to reach, it was the way he sustained that level. And that has made all the difference.

"A man with a thousand weapons in one racket -- each of them equally reliable." Simon Barnes on Novak Djokovic

For most of the match Murray seemed to be facing an opponent with too many ultra-reliable weapons. That's Djokovic for you. The one-man army of tennis. A man with a thousand weapons in one racket -- each of them equally reliable. You can only beat him via the Victoria Cross route of suicidal bravery. Murray tried that and fell short.

The one thing you can't afford is an off game. And that's always been a problem with Murray. Every now and then he'll go on a bit of a wander. Piece of advice: never take a stroll when there's a man with seven kinds of weapons waiting for you on the stairs.

If you have an off game against Djokovic it's almost impossible to find a way back. That's the level of consistency Djokovic has reached this year. A couple of errors and that's the set. An hour of your life you've just wasted. That's what happened in the first set and then the second set when the match began on Friday.

This kind of multi-weaponed consistency was too much for Rafael Nadal when he played Djokovic in the quarterfinals. The best clay-courter of all time was outgunned, and ended by running up the white flag.

And there was Murray in the clay-court form of his life, and it still wasn't enough. There was a glorious passage when Murray turned it round last night and carried on into today. Murray's golden period began with a ludicrous cross-court winner that he hit with his back to the court while chasing a lob.

He was on a hot streak, unplayable, when they came off court Friday night at 3-3 in the fourth set with a storm forecast. Djokovic was visibly eager to get off court. It was to Murray's huge credit that he was able to take things up again today. He played some inspired defence before turning to attack in the classic clay-court manner to take that fourth set.

And then guess what? An off game. While inevitably Djokovic kept his own level of play as high as ever, so he just rode away with the match. Getting back on level terms had taken everything that Murray had to offer.

The usual thing here -- at least among Brits -- is to blame Murray for those treacherous off games, for failing to sustain a level, for being beaten by a man he has ousted twice in grand slam finals. But I'm more inclined to wonder about the person on the other side of the net.

We know that Djokovic is one of the greats. The argument now is about his place among the greatest. We've been going through perhaps the finest era in the history of men's tennis in the past decade, with Roger Federer, Nadal and Djokovic. The argument has always been about whether Fed is better than Rafa; whether genius is a finer thing that inspired effort.

It's a terrific argument, but we should put it on hold now. This is the time of Nole. Djokovic has won one slam already this year; on Sunday he plays Stan Wawrinka in the final of another. By early evening Sunday he could be halfway to a calendar year grand slam. No one's done that since Rod Laver.

And when you bring the name of Laver into a tennis argument, you know you're talking about greatness rather than mere excellence. How did Murray, did Nadal, make those errors against Djokovic? Because Djokovic's extraordinary sustained level of excellence forces opponents to look for too much. Djokovic, more than any player I have ever seen, has the capacity to force the unforced errors from his opponent. Djokovic has the power to extort despair.

It's still a little early to go crazy, but don't take your eye off Djokovic. This could yet be one of the great years of tennis. We talk of Federer's time of utter supremacy, of Nadal's dominance in Paris. We might be one day talking about 2015 as the year of Nole. One-man army.