John Fetterman needles Dr Oz for once being a Yankees fan after Philadelphia team advances to World Series

John Fetterman is questioning the bonafides of his opponent’s Phillies fandom as the team celebrates its clinching of the National League pennant and prepares for the World Series.

The Pennsylvania lieutenant governor has relentlessly chipped away at Dr Mehmet Oz’s credibility as a Pennsylvanian throughout their tightening Senate race, which now appears to be neck-and-neck amid a wave of GOP reinforcements in the form of ad spending and coverage of the race from conservative media.

On Sunday he dredged up Dr Oz’s past attendance at a New York Yankees game, and asked his opponent: “My dude, isn’t your team still playing?” after Dr Oz posted a tweet in celebration of the Phillies’ come-from-behind victory over the San Diego Padres.

The Yankees would go on to endure a 4-0 defeat in a best-of-seven series against the Houston Astros, who will take on the Phillies for the World Series title.

Polls show the Pennsylvania Senate race tightening and potentially even swinging in the Republican Dr Oz’s favour in recent days as Mr Fetterman and his opponent head into the final weeks of the campaign. The race is one of the most significant in the nation given the potential for Democrats to flip a Senate seat held by a retiring Republican, Pat Toomey.

Mr Fetterman’s campaign has been buoyed by widespread support from fans around the nation on Twitter, but battered by his opponent’s questioning of his ability to serve as a US senator while he recovers from a stroke suffered in the final days of the primary earlier this year.

Also casting a shadow across the entire midterms field is the approval rating of President Joe Biden, which has rebounded in recent weeks but still remains underwater.