British number five Arvind Parmar saved three match points before beating Thai Paradorn Srichaphan 7-6 (7-3) 5-7 7-6 (9-7) at the Rotterdam Open.
The win was Parmar's first on the ATP tour since June 2004
The world number 230, who came into the tournament as a lucky loser, saved the three match points in the final-set tie-break before sealing his victory.
The surprise win is the 27-year-old's first at ATP level since June 2004.
He joins fellow Briton Greg Rusedski in the second round while Tim Henman faces Sweden's Thomas Johansson on Wednesday.
Parmar has played in only two Challenger events so far this season, in Wrexham and Bergamo, Italy, and lost in the first round both times.
He earned his place in the tournament as a replacement for top seed Rafael Nadal, who withdrew because of a thigh injury.
Rusedski, who overcame Czech Robin Vik in straight sets on Monday, faces Russian Nikolay Davydenko in the second round after the top seed beat Jan Hernych 6-3 6-3.