Guillermo Hormazabal defeated Guillermo Rivera Aranguiz 7-6 7-5 in the Chile F8 qualifying round on clay. The upset overturned the form book — Guillermo Rivera Aranguiz came in leading the head-to-head 2–1. Guillermo Hormazabal narrowed the head-to-head to 2–2.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2012-02-20 | Chile F3 | SF | clay | Guillermo Rivera Aranguiz | 7-5 7-6(3) |
| 2010-10-25 | Chile F2 | F | clay | Guillermo Hormazabal | 7-5 6-2 |
| 2010-10-18 | Chile F1 | SF | clay | Guillermo Rivera Aranguiz | 6-0 7-5 |
Averages over each player's completed matches in the selected window. ATP, WTA & Challenger.