New England Patriots star Tom Brady must serve a four-game suspension imposed by the NFL over claims he cheated by using deflated balls, a federal appeals court has ruled.

Monday’s 2-1 decision by the 2nd US Circuit Court of Appeals in New York is a boost to the league in its battle with the players’ union.

It overturns last September’s ruling by a Manhattan judge that went against the league, allowing the 38-year-old quarterback to play the whole season.

The appeals court said that NFL Commissioner Roger Goodell had properly exercised his discretion under a collective bargaining agreement when he imposed the suspension.

Opening of Ermenegildo Zegna Global Store

Delategate reportedly strained Brady’s marriage to supermodel Gisele

The NFL welcomed the ruling, but there was no immediate response from Brady.

It is the latest twist in a saga that has dogged Brady, one of the highest-profile athletes in the US and a record-equalling four-time winner of the Super Bowl.

NFL Commissioner Goodell exits the Manhattan Federal Courthouse in New York

Monday’s decision backed up NFL Commissioner Roger Goodell

The controversy, dubbed Deflategate, centred on footballs used by the Patriots in their 45-7 win over the Indianapolis Colts in the AFC Championship Game in January 2015.

Brady’s team went on to win the Super Bowl.

An NFL-hired investigator determined in May last year that Brady was probably aware of a plan by locker room staff to deflate the footballs below league standards, making them easier to grip in cold and wet conditions.

Days later the NFL imposed the four-game suspension against Brady, a decision the league upheld in July.

The NFL also fined the Patriots $1m over the under-inflated footballs.

The scandal reportedly put a strain on Brady’s seven-year marriage to supermodel Gisele Bundchen, with whom he has two children.