EVER since they were teenagers plotting their respective paths through the sport, Andy Murray has always measured himself against Rafa Nadal. While it was the discovery that the Mallorcan was hitting regularly with Carlos Moya which first prompted Andy to spend the formative years of his development in Barcelona, now it is Nadal who seeks to use the Scot as a touchstone. Victory for the Spaniard against the World No 2 from Dunblane in their round robin match at the ATP World Tour finals this afternoon would be a further barometer of his progress on his gradual return from the illness and injury which caused him to take the last three months of the 2014 season off.

Murray-Nadal is one of the great match-ups in tennis, but it is a lesser spotted one. While Tuesday's meeting between Novak Djokovic and Roger Federer was the 43rd in the series, a grudge match which has occurred more frequently than any in history, including 12 times, most of them finals, in the last two calendar years, Murray and Nadal have met just 21 times in roughly the same time span. While the Spaniard has won no fewer than 15 of them, this will be their first meeting on a hard court since Japan in 2011, while the pair's only meeting this year appeared to signal a step change in the relationship. On his home clay in the final of Madrid, Murray swatted the Spaniard aside 6-3, 6-2 to take the title.

Nadal's play has improved since then, though, as witnessed by back-to-back finals on the tour in recent weeks. Murray feels the court conditions suit him and expects to be pushed to the limit, as he was at this venue back in 2010, when Nadal sneaked an epic three-set victory on a tie-break. The winner will have all but secured his place in the semi-finals.

"Obviously I haven't played Rafa loads over the last couple of years," said Murray. "We only played once this year, in Madrid. That was the last time we played. But he's starting to play better again. We played a great match here a few years ago. I think the court surface is good for him, as well. So it will be incredibly hard. But I feel like I'm playing well enough to win. "

Who exactly the surface will suit is something of a moot point. This tournament has been notable for one-sided, blow-out wins over the past few seasons, a fact attributed variously to differing levels of motivation late on in the season, or the ability of one player or other to dominate from the baseline in slow conditions. Nadal was playing down expectations after an impressive opening win against Stan Wawrinka, an opponent who was universally slammed for his lacklustre contribution.

"Obviously is an opportunity for me to compete against the No 2 in the world," said Nadal. "Andy is a player who has had a great season, a fantastic player on every surface, but this especially is one which he likes to play. I'm excited to play the match but I only take it as an opportunity to play against him, to try to play a good match. I cannot think about that [winning the competition], seriously. I haven't won enough this year to think about these kind of things."

The Spaniard has won just one career tournament indoors, compared to 46 outside, and attempted to explain why. "I think the feeling on the ball is different than in outdoor." he said. "The things that during all my career worked very well in outdoor courts, in indoor have been more difficult. The topspin is less important. The serve gets bigger impact in indoor than in outdoor. Wind is not there. I like to play with more different conditions. I have played good tournaments indoor, too. But I believe the opponents I have here feel them play a little bit better than me."

There were smiles yesterday when Murray's preparations for the match included a hit with left-hander Greg Rusedski, his former British Davis Cup team-mate sending one ace past the World No 2 and the Scot having a laugh when asked if the former US Open runner up "still had it". Despite the reports of his demise in the last 18 months, Nadal still has it all right. This afternoon's match will be serious business.