Tennis authorities have launched an inquiry into insider trading after suspicious betting on a minor first-round match at Wimbledon that drew more than £1 million in wagers from punters.

The Tennis Integrity Unit, an anti-corruption group set up by the international tennis authorities, was tipped off yesterday over "concerns" about a Wimbledon match involving Jürgen Melzer, an Austrian ranked No 30 in the world, and Wayne Odesnik, 23, a South African-born American ranked 109. Melzer was the clear favourite to win, but bookies were alerted by the strength of betting on a three sets to love victory. Melzer eventually won 6-1, 6-4, 6-2.

Betfair, the internet betting site, reported that around £650,000 was punted before the match started, with another £400,000 flooding in during play, the vast majority of wagers on Melzer. Ladbrokes and Paddy Power were among high-street bookies who suspended betting before the match, as did many online operators.

The Integrity Unit will focus on whether punters were privy to any insider information. Odesnik had suffered a minor muscle injury on Monday, although the player insisted that he was fit and well and that he had not told anyone of his injury, nor had he been approached by a potential match-fixer. But on Betfair alone, £350,000 was traded on a 3-0 Melzer victory with odds falling as short as 1-9. This was a low profile match between relatively unknown players on an outside court with little public interest that would normally attract about £10,000 worth of bets.

"I have no idea about any of this," Odesnik said. "I am just here to play. I am a young guy with a good future ahead of me and I would never do anything to risk that."

Melzer said that Odesnik told him at the net that he was suffering a "muscle tweak" but the Austrian had expected to win convincingly given Odesnik's lack of experience on grass.

However, the outcome of the tie merely underlines the constant fear that stalks modern tennis, particularly as the sport spreads east into new and emerging markets, such as Russia, China and India, known to be prone to corruption and match-fixing. The authorities now have what they call a "watch list" of between six and 12 players - particularly Russians, Argentines, Italians and Spaniards, who are under scrutiny because of past involvement in matches where suspicious betting occured and match-fixing was suspected.

News of the inquiry at the All England Championships came after The Times revealed that the Tennis Integrity Unit was already investigating a match played in a pre-Wimbledon tournament involving Daniel Kollerer and Oscar Hernandez. Betting on the match was voided after bookies spotted suspicious betting patterns.

Hernandez crashed out of Wimbledon yesterday, losing 6-0, 6-0, 6-4 to Argentinia's Leonardo Mayer. The Spaniard was clearly unhappy and refused to speak to reporters afterwards.