World No2 Roger Federer Photo: Marianne Bevis
So all eight men had displayed their wares. Now, on Day 3, it was beginning to get a little serious for some of them: the four losers.
One of those losers, Rafael Nadal, would of course play no further part, his place taken by the fresh, and fresh-faced Pablo Carreno Busta, who right up until the last day of qualification for London, had good reason to think he may make the top-eight cut in his own right.
Jack Sock’s title run at the Paris Masters knocked him into ninth place, but he would still have his moment in the sun come Wednesday, courtesy of his compatriot’s misfortune.
But what of the other opening-match losers who were still in contention at the O2? Although the writing was on the wall, it did still remain in a very light script, for the permutations surrounding the notorious round-robin format are many and varied. Indeed there are even scenarios where a player with a single match-win against his three opponents could still make the cut.
But a few options were becoming clearer, particularly as Roger Federer, top seed in the Boris Becker Group, was the only one of the four to win his opener in straight sets. Should he win his second match in the same way, he was into the semi-finals. If he won in three sets, and the man he beat in his opener, Jack Sock, beat the other group loser, Marin Cilic, Federer would also qualify.
But all that remained hypothetical until Federer stood across the net from the other…