United States President Donald Trump met with “thunderous” booing from fellow New York Knicks fans when he attended the National Basketball Association (NBA) finals in New York’s Madison Square Garden on Monday, despite being the first sitting president ever to attend.Security was heightened for his visit, with authorities barring fans without tickets from coming within several blocks of the venue.Here’s what happened.What happened?Fans jeered the president, who was watching the game against the San Antonio Spurs from an executive suite when he appeared onscreen inside the arena during the singing of the national anthem.Seen on the Jumbotron – a giant screen – saluting the US flag during the national anthem, Trump received a chorus of boos but played down the reception after the game – a 115-111 Spurs win that cut the Knicks’ series lead to 2-1.The Athletic reported that Trump, 79, a native New Yorker, drew louder boos than the rivals, the Spurs.White House pool reporters said the president had been booed “thunderously”.NBA commissioner Adam Silver said Trump was very welcome to attend the first NBA Finals game in New York since 1999, when the Knicks lost to the Spurs, adding that the president is a “genuine Knicks fan”.“What makes sports so special, especially when there’s so much that divides …