The US president ‌presented the popular Irishman with the trophy at the west of Ireland course owned by the Trump family on Sunday after Lowry had trounced the field for a remarkable 11-stroke win.

Trump was among the spectators ‌during a 48-hour visit to Ireland. He arrived on Saturday after meeting Irish leaders in Dublin, forcing play to pause while his presidential ‌helicopter landed between a fairway and a nearby field of cows.

Lowry, who described Saturday's interruption as "an insane day", had taken control with an eight-under course record the day before and came one shot from matching it on Sunday, draining an 18th hole birdie to finish with a 23-under-par total.

"He was unbelievable. He's a great guy," Trump said of Lowry, before further delighting the home ‌fans by saying ‌he was going to ⁠take tariffs off Irish whiskey.

Lowry, who fought back tears as he paid tribute to ​his family at the end of his round, thanked Trump and Irish Prime Minister Micheal Martin for being at the event, saying it was amazing to have a US president in attendance.

Donald Trump presents Shane Lowry with the Irish Open trophy. PHOTO: Getty Images.

The 2019 Open champion's record 11-shot victory came 17 years after he became just the third amateur player to win a European Tour event at his home tournament.

Trump, wearing a suit ⁠and white USA cap, greeted Lowry on the first tee and watched ‌from a ​few feet away as he teed off. Trump told reporters that Lowry was "playing great", with Lowry later laughing at how it had been "a bit mad" ​to have the President watching on.

While thousands of anti-Trump protesters marched through Dublin on Saturday, the president was cheered heartily throughout Sunday ​and during a brief appearance in the club bar in the adjoining hotel where he stayed on Saturday night.

Trump watched the action on both days from an 18th-green balcony alongside his sons, Don Jr. and Eric and some ​of ​his grandchildren. He was joined by U.S. major ​champions Brooks Koepka and Patrick Reed, who finished in second place.

Lowry finished on a 257 total, seven shots better than the previous 72-hole record of 264 by Jon Rahm at Lahinch in 2019.

Reed shot 64 and Joaquin Niemann 67 to finish in joint-second place, while the leading Australian was David Micheluzzi, who ended a decent week in style with a last-round 65 that left him tied for 23rd on four-under.