An ATP Tour match is being investigated by the Tennis Integrity Unit over suspicious betting patterns

Some bookmakers suspended markets on the meeting between Alexandr Dolgopolov and Thiago Monteiro at the Winston-Salem Open in North Carolina on Sunday.

Brazilian Monteiro, the world number 114, won the match 6-3 6-3 against the Ukrainian, a former top-20 player now ranked 63.

Dolgopolov's odds drifted dramatically before play began, prompting the TIU to launch a probe into potential match-fixing.

A TIU statement read: "The Tennis Integrity Unit was made aware of concerns over betting patterns during the match between Alexandr Dolgopolov and Thiago Monteiro at the ATP World Tour event in Winston-Salem, USA, yesterday (Sunday, August 20).

"As with all match alerts, the TIU will assess, make a judgement and take appropriate action on the information received through its co-operative agreements with betting operators."

Last month the TIU announced three matches at this year's Wimbledon would be investigated.

Alerts were triggered on two matches at the qualifying event at Roehampton and one from the main draw at SW19.

The Unit stressed that alerts on their own were not evidence of match-fixing. Any investigation can take several weeks or months.