Barclays ATP World Tour Finals: Rockin' Robin.

After the round-robin stage of the prestigious end-of-year bat ‘n' ball extravaganza, the semi-finalists have been decided. Roger Federer will play Nikolay Davydenko and Juan Martin Del Potro will play Robin Söderling for a place in Sunday’s final.

A far cry from the sedate all-whites of SW19, the action in the Greenwich O2 Arena has been an oxymoronic corporate rock ’n' roll affair. The combatants enter the arena to the sound of The Clash’s punk classic “London calling” and do battle on a Barclays Bank blue piste.

Group A (Federer, Murray, Del Potro, Verdasco)

Andy Murray looked in decent nick in his opener against Del Potro. His array of spins and squash shots managed to tame the straight hitting of the Argentine over three sets.

The crucial match was Murray vs. Federer. It was like watching a talented up and coming musician exhibiting his skills in the guitar shop, only for Jimi Hendrix to walk in and steal the show. Seemingly needing a set to get calibrated (he had also dropped the opening set in his opening win against Verdasco), Federer was simply majestic in sets two and three – I can’t recall seeing any tennis better than this. When he has his muse, the racquet is a natural extension of his body and anything feels possible; one shot in particular, he has made his own - where the ball is taken between the half-volley and the groundstroke and caressed for winners from all positions. Earlier, Del Potro had seen off a spirited Fernando Verdasco in a final-set tie-break, giving himself a chance of qualifying.

In the third round of matches, Murray broadly did what he had to do – beat Verdasco (who, despite losing all three of his games, was certainly not the whipping boy most expected him to be) but crucially, not in straight sets, leaving him vulnerable in the event of a close Del Potro victory over Federer.  This match was strangely similar to the US Open final in tenor, it was almost as though it had been transposed from New York to London - Del Potro’s power ultimately holding sway over Federer’s guile. Indeed, it really should have been a straight sets victory for Del Potro but he faltered in the second set tie-break, netting a relatively easy shot at 5-4 to the good. A relieved Federer (he would have exited at this stage) seemed to be just going through the motions in the third set, which Del Potro took 6-3, the only scoreline which could send Murray out. Because all three players were tied in the number of matches won and the percentage of sets won, it came down to the percentage of games won. Federer was clear (judging from his reaction at the end, he seemed to have done the math beforehand) and Del Potro had won one more game than Murray with the same number lost. Harsh? A tad but perhaps if he had read the small print, Murray would have put a bit more in somewhere. Not a disaster for Murray in the grand scheme of things but does he really need five-six-seven(?) people geeing him up – that’s four-five-six bods too many in my book.

Group B (Nadal, Djokovic, Davydenko, Soderling)

After straight sets victories over the world numbers two and three, Nadal and Djokovic, the Swede Robin Söderling was the first man to qualify for the semis. The surprise was not the fact that he won the matches but the ease with which he did so, especially against the Serb.

Söderling has the understated disposition of a doubles player, from his irony-free ball toss onwards, his game is all about good honest powerful hitting and it was too much for Nadal and Djokovic, who seemed to be running on empty throughout the tournament.

This correspondent got to see Nadal vs. Davydenko in the second round of matches, which proved to be one-way traffic. Both players needed the victory after first round defeats. The Spaniard had huge support from the crowd but he was all brawn and no brain; the hard courts don’t suit Nadal’s attritional top-spin game and an in-form Davydenko was way too skillful, dominating the play and easily winning in straight sets.

In the third round of matches, an off-colour Djoko saw off an even offer-colour Rafa to give himself a chance of qualifying. But it wasn’t to be, as Davydenko rose to the occasion to beat Söderling in three sets. By offering some serious money to win each match and, further, to go through the whole tournament undefeated, the circumstance of a player not giving it his all doesn’t really obtain, so it was full credit to the Russian to beat the man of the moment.

For all Söderling’s form, it is hard to look beyond a Federer vs. Del Potro final.