Marek Semjan
Marek Semjan is a Slovak tennis player playing on the ATP Challenger Tour. On 30 August 2010, he reached his highest ATP singles ranking of 218.
He won over Fernando Verdasco in Prostějov in three sets 6-4, 6-7, 6-4.
Challenger finals
Singles: 2 (0–2)
| Outcome | No. | Date | Tournament | Surface | Opponent in the final | Score |
| Runner-up | 1. | 1 August 2010 | Saransk, Russia | Clay |  Ivan Sergeyev | 6–7, 1–6 |
| Runner-up | 2. | 14 August 2010 | Samarkand, Uzbekistan | Clay |  Andrej Martin | 4–6, 5–7 |
Doubles: 2 (2–0)
| Outcome | No. | Date | Tournament | Surface | Partner | Opponents in the final | Score |
| Winners | 1. | 23 November 2008 | Yokohama, Japan | Hard |  Tomáš Cakl |  Brendan Evans  Martin Slanar | 6–3, 7–6 |
| Winners | 2. | 12 June 2010 | Košice, Slovakia | Clay | Miloslav Mečíř Jr. |  Ricardo Hocevar Caio Zampieri | 3–6, 6–1, |