Russian Daniil Medvedev will climb to No.2 in the ATP world rankings later this month - with this small step signalling that, for the first time in 16 years, big change may be afoot in the men's game.

The leading two positions in the rankings have been occupied by a combination of the 'Big Four' ever since Rafael Nadal climbed above Lleyton Hewitt to take second place on the ladder on July 25, 2005.

Nadal, Roger Federer, Novak Djokovic and Andy Murray have all had spells at No.1 in the years since then, and no other player has had a look-in on those leading two positions.

Within days, however, that is about to change, as the younger generation of players gains a first foothold in the top two.

The ATP, which runs the men's game, said on Saturday that the 25-year-old Medvedev is certain to nudge up one place from his current position of world No.3 when the rankings are published on March 15.

The Russian is currently on 9,735 points, 115 points behind Nadal, and he has a first-round bye at the Open 13 Marseille tournament next week.

The ATP tweeted: "Medvedev will be the 1st player in the Top 2 since 25 July 2005 other than the Big 4 of DjokerNole, RafaelNadal, rogerfederer and andy_murray."

Medvedev, who won the ATP World Tour Finals title in November and reached the Australian Open final last month, missed an early chance this week to move ahead of Nadal when he lost surprisingly in the first round of the Rotterdam Open.