Tetsuya Chaen defeated Danai Udomchoke 6-4 4-6 6-0 in the Japan 1 Masters 1 round of 16 on hard. The upset overturned the form book — Danai Udomchoke came in leading the head-to-head 1–0. Tetsuya Chaen claimed a first win over Danai Udomchoke in two meetings, levelling the head-to-head at 1–1.
Chaen T. came through in three sets.
Tetsuya Chaen beat Danai Udomchoke 6-4 4-6 6-0. Umpiry, "Tetsuya Chaen vs Danai Udomchoke — Japan 1 Masters 1 Round of 16", https://umpiry.com/match/1999-06-07/chaen-vs-udomchoke-japan-1-masters-1-r16?utm_source=cite (as of 7 June 1999).