Emmanuel Macron is keeping a tight grip on France’s relationship with the U.S.

So tight, in fact, that the handshake the French president shared with President Trump at the G7 meeting in Canada on Friday night left a white thumb print on Trump’s hand.

“Arm wrestling, he would be very, very tough,” Trump said during the meeting, adding of Macron, “He’s my friend, we have had a great relationship from the very beginning.”

The leaders have a history of notable handshakes, including another white-knuckle affair at the White House in May 2017 and a 30-second, two-handed extravaganza at Bastille Day celebrations in France in July that went viral on social media.