Currently ninth in the point standings, Lapentti's victory over the 27th-ranked Hewitt helped his chances of moving into the top eight and qualifying for the prestigious event at Hanover, Germany.
The Ecuadorian, who never had won a match on carpet and had only two career indoor victories before this tournament, had to struggle to reach the final. He came back from a set down in each of his four previous matches, saving two match points.
"No one expected me to do anything indoors," said Lapentti, ranked a career-high 14th, up from 69 at this time last year. "I was so close to losing twice this week."
Going into the match, the two players appeared evenly matched, both having won two career titles including one each this year and both seeking their first career indoor title.
Lapentti got off to a strong start, breaking Hewitt's opening serve and taking a 3-0 lead.
His confidence building as Hewitt's sputtered, Lapentti surrendered only two more points on his serve, easily holding to take the set.
Lapentti began the second set the same way, breaking Hewitt's serve twice for a 3-0 lead.
"I got off to a bad start
South Africa's Piet Norval and Kevin Ullyett of Zimbabwe won the doubles title, 4-6, 7-6 (7-5), 7-6 (7-4) over the fourth-seeded team of 1995 singles champion Wayne Ferreira of South Africa and Australia's Sandon Stolle.
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