René Lacoste first became world No. 1 in 1926.
The ranking reflects the influential year-end assessments of the period, when tennis did not yet have the standardized computer rankings used today. A. Wallis Myers, the Daily Telegraph’s respected tennis correspondent, placed Lacoste at No. 1 for 1926.
That season included a major breakthrough at the U.S. National Championships, the tournament now known as the U.S. Open. Lacoste defeated Jean Borotra in the final, 6–4, 6–0, 6–4, earning his first U.S. title after losing the French Championships final to Henri Cochet.
Historical lists can differ because several journalists and tennis authorities issued their own rankings. Nevertheless, 1926 is the accepted first year associated with Lacoste’s world No. 1 status. He was also ranked No. 1 in some contemporary assessments for 1927 and 1929, underscoring his place among the era’s leading players.