Unheralded Igor Kunitsyn upset former world number one Marat Safin 7-6, 6-7, 6-3 in an all-Russian Kremlin Cup final to clinch his maiden title on Sunday.
Earlier, world number one Jelena Jankovic overpowered Vera Zvonareva 6-2, 6-4 in the women's final to win her third title in a row.
The 71st-ranked Kunitsyn, playing in his first ATP final, earned a decisive break in the sixth game of the final set, then held his nerve to seal victory with an ace down the middle.
"This is beyond my wildest dreams," Kunitsyn told reporters.
"I'd never have expected to beat Marat in the final in Moscow," added the 27-year-old from Vladivostok, who took home $171,000 in winnings to more than double his earnings for the year.
Safin, seeded seventh and bidding to claim his first title in almost four years, reached the final without hitting a ball when his semi-final opponent, German Mischa Zverev, withdrew with illness on Saturday.
The big Russian has not tasted success since winning the Australian Open in January 2005.
"I have only myself to blame," said Safin, who also lost to compatriot Nikolay Davydenko in the 2006 final in Moscow.
"If I had won the first set, it would have been a different story but he gained confidence as the match went on, played well in the end and deserved his victory."
Jankovic, making her debut in Moscow, broke Zvonareva twice to take the first set in just over half an hour.
The in-form Serbian, who also beat the Russian on her way to winning titles in Stuttgart and Beijing in the past two weeks, led 4-2 in the second but allowed the seventh seed to break back to level at 4-4.
The top seed, however, earned another break in the ninth game before going on to clinch victory after 81 minutes when Zvonareva overhit her forehand on matchpoint.
"I've played her twice in the last two weeks so I really knew what to expect and was focussed right from the start," said Jankovic, who pocketed $196,900 for her efforts.
"I dominated in the first set but in the second my concentration slipped a little bit but I was able to get myself together in the end."
The 23-year-old has been playing almost non-stop in the last couple of months and must keep going for another week before taking a well-deserved rest.
"I've worked really hard in the last three weeks, winning three titles in a row. It's not easy," she told reporters.
"But I still have my commitments to play next week in Zurich. Then I'll take a two-week rest before playing (next month's season-ending WTA Championships) in Doha.
"I've had a tough season, overcoming a number of injuries but I'm quite close to finishing the year ranked number one and I'm really proud of it," she added.
Zvonareva, who reached her first Kremlin Cup final on her eighth appearance in Moscow, said she could do little to stop Jankovic.
"It seems she had an answer for everything I tried," the 24-year-old Muscovite told a news conference.