LONDON — Saying tennis is “potentially at a crossroads,” an independent review panel found 45 matches that merit further investigation because of irregular betting patterns and offered a host of recommendations to the sport’s leaders for combatting corruption.

The panel’s 66-page report, prompted in part by suspicions surrounding a match last year involving fourth-ranked Nikolay Davydenko, was released yesterday by the International Tennis Federation, the ATP, the WTA Tour, and the four Grand Slams.

The 45 unidentified matches, played in the last five years, were among 73 examined by the panel, which warned of “inside information.” The review was prompted by a series of events connected to gambling in tennis.

Most prominently, an online betting site, in an unprecedented move, voided all bets on a match involving Davydenko last year because of suspicious gambling patterns. The site received about $7 million in wagers on the match, 10 times the usual amount, and most of the money backed 87th-ranked Martin Vassallo Arguello — with some coming in even after he lost the opening set. The match ended when Davydenko quit in the third set, citing a foot injury. An ATP inquiry is ongoing.

“The name ‘Davydenko’ is being abused,” his manager, Ronnie Leitgeb, said yesterday from Poertschach, Austria, where the Russian is playing. “If his name keeps coming up in rumors and nothing has been proven in the upcoming two or three months, we’ll consider taking legal action.”