Kristal played as a midfielder for Lõvid, Sport Tallinn, Flora, FC Lahti and the Estonia national team.

Kristal made his international debut in Estonia's first official match since restoration of independence on 3 June 1992, a 1–1 draw against Slovenia.

Kristal began playing football for a local club Tallinna Lõvid (Lions of Tallinn), where he was coached Roman Ubakivi.

[6] Kristal made his international debut for Estonia on 3 June 1992, replacing Urmas Kirs in the 77th minute of a historic 1–1 draw against Slovenia in a friendly at Kadriorg Stadium.

[7] Kristal finished his international career with a testimonial match on 20 April 2005, a 1–2 home loss to Norway.