That position was based on his early season form on clay, when he won four titles, including beating Gustavo Kuerten in the MastersSeries event in Rome in the build-up to Roland Garros.
But he has been surpassed by Rafael Nadal on the list of all-time MastersSeries titles after the Spaniard won in Rome to match record-holder Andre Agassi on 17.
The Monte Carlo resident made it to final of the Madrid MastersSeries event and the last four of the Rome and Toronto Masters, as well as reaching at least the semi-finals stages in five other tournaments.