|Born||20 October 1960
Bonn, West Germany
|Height||5'9" (175 cm)|
|Highest ranking||No. 74 (09 Apr 1984)|
|Grand Slam Singles results|
|French Open||3R (1982)|
|Wimbledon||1R (1984, 1985)|
|US Open||3R (1985)|
|Highest ranking||No. 157 (26 Nov 1984)|
|Grand Slam Doubles results|
|French Open||2R (1983)|
|US Open||1R (1984)|
Ostoja was the Yugoslavian National Champion in 1978, having earlier won the event as a junior, in the 14s, 16 and 18s age groups.
He had his best year on tour in 1981 when he won his first career title at Brussels and reached the doubles finals of the Austrian Open. The Croatian also reached the semi-finals in Stowe, Vermont, that year.
At Cologne he put some good performances together in both 1983 and 1984, with quarter-final and semi-final appearances respectively.
Ostoja reached another Grand Slam third round in the 1985 US Open. He had one of the best wins of his career at the Lipton International Players Championships in Delray Beach that year, defeating world number six Henrik Sundström in straight sets.
Grand Prix career finals
Singles: 1 (1-0)
|Outcome||No.||Year||Tournament||Surface||Opponent in the final||Score in the final|
|Winner||1.||1981||Brussels, Belgium||Clay||Ricardo Ycaza||4–6, 6–4, 7–5|
Doubles: 1 (0–1)
|Outcome||No.||Year||Tournament||Surface||Partner||Opponents in the final||Score in the final|
|Runner-up||1.||1981||Kitzbühel, Austria||Clay||Louk Sanders|| David Carter
|No.||Year||Tournament||Surface||Opponent in the final||Score in the final|
|1.||1983||Tampere, Finland||Clay||Scott Lipton||6–4, 6–2|
|2.||1986||Lisbon, Portugal||Clay||John Frawley||6–2, 2–6, 6–2|
|3.||1988||Strasbourg, France||Clay||Tomas Nydahl||6–2, 6–2|
|No.||Year||Tournament||Surface||Partner||Opponents in the final||Score in the final|
|1.||1981||Barcelona, Spain||Clay||Junie Chatman|| Francisco González