Marko Neunteibl defeated Juan Martin Aranguren 6-2 6-4 in the Colombia F1 round of 32 on clay. The upset overturned the form book — Juan Martin Aranguren came in leading the head-to-head 2–0. Marko Neunteibl claimed a first win over Juan Martin Aranguren in three meetings, narrowing the head-to-head to 2–1.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2004-10-25 | Chile F2 | R32 | clay | Juan Martin Aranguren | 3-6 7-6(2) 7-5 |
| 2004-03-08 | Chile 1 2 | R16 | clay | Juan Martin Aranguren | 6-2 7-5 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.