Dewulf appeared in 1989 at the junior tournaments of the French Open and Wimbledon , where he failed in the first round. In doubles he reached the second round with Tom Vanhoudt . The following year he entered the junior competition at Wimbledon again, this time he was defeated in both singles and doubles in the first round. In 1990 he became a professional tennis player and was able to win two singles titles and one double title on the ATP World Tour during his career . He also won a single and six double titles on the ATP Challenger Tour . He reached the highest ranking in the tennis world rankings in 1997 with position 39 in singles and in 1993 with position 125 in doubles.
His best individual result at a Grand Slam tournament was reaching the semi-finals of the 1997 French Open. First, he played his way through three qualifying rounds, defeating Stefano Pescosolido , among others . This was followed by victories over Cristiano Caratti , Fernando Meligeni , Albert Portas , Àlex Corretja and Magnus Norman . In the semifinals he was finally defeated by the later champion Gustavo Kuerten . In the doubles competition, he never appeared in a Grand Slam tournament.
Dewulf played 28 singles and 14 doubles games for the Belgian Davis Cup team between 1991 and 2001 . He had his greatest success with the team in 1999 when he reached the semi-finals of the world group with Belgium. France finally won 4-1, Dewulf lost his individual in five sets against Cédric Pioline .
Belgium
Vienna
Julián Alonso
Umag