Jamie Murray is the new doubles world number one.
The Scot will become the first British player to be officially ranked as number one in the world despite being knocked out of the Miami Open in the first round.
The current leading men's doubles player, Marcelo Melo - playing alongside Ivan Dodig - lost in the second round of the competition on Sunday.
Last year, the 32-year-old made the semi-finals of the tournament, so the result means he will lose more ranking points than Murray - who was knocked out in round two last year.
Murray, 30, was beaten in the first round of this year's Miami Open with partner Bruno Soares - his 63rd partner in 13 years.
However, when the rankings are updated on April 4 he will have five points more than Melo.
Former Wimbeldon singles winner and four-time Grand Slam women's doubles winner Virginia Wade was ranked first in the women's doubles ratings - but the official rankings were not brought in until 1975.