British number one Emma Raducanu has withdrawn from the Madrid Open with a hand injury hours before her first-round match.

Raducanu's withdrawal means she is almost certain to drop out of the world's top 100.

The 2021 US Open champion has been hindered by a wrist problem in recent months.

Raducanu's most recent appearance was a 6-2 6-1 defeat by Jelena Ostapenko in the first round of the Porsche Tennis Grand Prix in Stuttgart this month, after which she dropped to 85 in the world rankings.

She skipped Great Britain's Billie Jean King Cup defeat by France to prepare for the clay-court part of the season.

Defeat in Stuttgart was her second in a row in the opening round, after losing to Bianca Andreescu in the Miami Open last month.

Raducanu suffered discomfort in her right wrist against Andreescu and later said she must find a long-term solution.

The injury ended her 2022 season early and returned before Indian Wells this month, when Raducanu reached the last 16 despite preparations also being hampered by tonsillitis.

Raducanu, who has played only 10 matches this season, is due to compete in the Italian Open in Rome starting on 8 May, before the French Open begins on 28 May.