Singles: 1 (1 title) Pro tour He won his first career title on clay in Valencia at the age of 19, defeating
Gilbert Schaller in the final. He was the youngest winner on tour for that year, 1995, and the next year as well when he defeated
Younes El Aynaoui in the final in Jakarta for his second title. Schalken managed to win at least one
ATP tournament eight out of nine years from 1995 to 2003, the sole exception being 1998. Schalken won his fourth title against
Tommy Haas in
Auckland in January 1999, exactly three years after his younger brother died of cancer, and dedicated the victory to him. He overcame
Marcelo Ríos to win the event in Boston in 1997. During the 1990s Schalken's Grand Slam record was meagre, amassing a win/loss total of only 4–14 up until the start of 1999. It took him until his 29th major to finally get past the third round. At Wimbledon he suffered final-set defeats three years in a row, losing in 1998 to
Jan-Michael Gambill 8–6 in the fifth, in 1999 to
Jim Courier 13–11 in the fifth, and in 2000 in a 5-hour, 5-minute marathon to
Mark Philippoussis 20–18 in the deciding set, the longest ever final set in Wimbledon men's singles history at the time (his record was later beaten by John Isner and Nicolas Mahut in 2010). Afterwards he was moved to comment, "I think Wimbledon doesn't want to have me in the fourth round." It was at the very same tournament two years later that Schalken made his Grand Slam breakthrough. He came into Wimbledon on the back of an outstanding grass-court season, in which he had made the semifinals at Queen's Club losing to eventual champion and world No. 1
Lleyton Hewitt before going on to win the title the following week in 's-Hertogenbosch, his first title on home soil and his first trophy on grass. Benefiting from a draw that opened up, he progressed past unseeded big servers
Jeff Morrison and
Jan Vacek in straight sets to reach a quarterfinal encounter with Hewitt, where he once again came undone in five sets. From being 6–2, 6–2 down, he squeezed out a third set tiebreak, ran away with the fourth 6–1 and was twice up a break early in the deciding set, as well as having a chance to serve for the match at 5–5, but his advantage was always short-lived; Hewitt broke to take the contest 7–5 in the fifth. However, Schalken remained the only man to take any sets off Hewitt for the entire fortnight, and finished with a grass-court record of 12–2, second only to the world No. 1 (14–0). Buoyed by this success, he very soon surpassed his quarterfinal achievement at the US Open, where he benefited in the opening round from a retirement by Mark Philippoussis when the Australian reinjured his troublesome knee, having led two sets to love. Schalken moved through to the second week beating
Ivan Ljubičić and
Sargis Sargsian, where on the
Arthur Ashe Stadium, he bested former world No. 1
Gustavo Kuerten in the last 16 and
Fernando González in the quarters. Both matches were littered with tiebreaks and decided upon them too, with Schalken proving the steadier man in the end; however, he still lost as many as he won, and this proved to be his undoing in the semifinals against eventual champion
Pete Sampras, coming out on the wrong end of two close tiebreaks before falling 6–2 in the third set. 2003 proved to be Schalken's most solid year, in which he compiled a best-ever 41–24 win–loss record and once again turned in good Slam performances at Wimbledon and the US Open. In early May 2003, he reached a career-high singles ranking of world No. 11 and stood one more outstanding result away from the top 10, but a quarterfinal loss in Munich to
Yevgeny Kafelnikov scuppered his chances. Nevertheless, he once more excelled on grass, defending his 's-Hertogenbosch title with a repeat win over Frenchman
Arnaud Clément in the final, before matching the previous year's quarterfinal at Wimbledon. Again he lost to the eventual champion, but this time the outcome was never in doubt, as he lost 6–3, 6–4, 6–4 to
Roger Federer for the fourth time that year in straight sets. After an unremarkable summer hardcourt season, Schalken arrived at the US Open and successfully defended the majority of his semifinalist points; for the fourth time in a little over a year he lost to the future champion, this time a straight-sets demolition at the hands of
Andy Roddick in the quarters. However, he got over the loss quickly; the following week he flew south to the tournament in Costa do Sauipe, Brazil, held on hardcourt for the last time, and captured the title with a 6–2, 6–4 win over
Rainer Schüttler, his third win over the German that year after Wimbledon and US Open victories. With the title Schalken became only the second active player after
Andre Agassi to win tournaments on five different continents. Schalken won just one match in a series of indoor tournaments that October, but other things were on his mind; he married his fiancée Ricky Pfennings on 21 November. The following year, 2004, began promisingly enough with a semifinal showing in Chennai followed by a first ever run to the second week in Australia, where he was defeated by Andy Roddick. But his form then took a sharp downturn and he managed only one quarterfinal in the next five months, a period that reached its lowest point when he was defaulted from his match with
Guillermo Cañas at the Masters Series event in Miami for verbally abusing the umpire. Only when Schalken had to pull out of Roland Garros, ending a sequence of 35 straight majors played, did it become clear that something was wrong physically. At the end of the year he was diagnosed with
mononucleosis, a debilitating virus that limited his strength; his one achievement was to reach a third consecutive Wimbledon quarterfinal, where for the third time in the space of a year he fell in straight sets to Andy Roddick in a 7–6, 7–6, 6–3 defeat. Having to miss the US Open, Schalken returned in the autumn without success and then played at the Australian Open the following January, where he lost to big-serving Swede
Joachim Johansson in straight sets. His 2005 season proved as limited as the second half of 2004 had been, his most notable results being two five-set victories against Swiss players
Marco Chiudinelli and
Stanislas Wawrinka in the Netherlands' Davis Cup win over Switzerland. He injured his right Achilles tendon in the spring and was forced off the tour in July, since then his only tournament at any level to date has been a semifinal showing in the Bergamo
Challenger in Italy in February 2006. == ATP career finals==