Dino Chiesa, the former karting manager of Nico Rosberg and Lewis Hamilton, was moved to tears by the outcome of their Formula One title duel on Sunday.
Rosberg finished second behind Mercedes team-mate Hamilton in the Abu Dhabi Grand Prix to secure his first drivers' championship, the Englishman having already claimed the crown on three occasions in his career.
Chiesa watched over the pair at karting team MBM, a joint venture between Mercedes and McLaren, and was delighted to see the German match the achievements of his fierce rival.
"I'm feeling really moved because I know what Nico Rosberg is thinking right now, I've known him for so long," he said.
"He was just waiting for this moment. He kept calm despite [being] behind Hamilton all race long and the British was trying to slow him down. He kept calm and he deserved to win the title because he was perfect until the last race.
"He waited a lot of years for the title and finally he can tell ... everybody that he is the world's champion.
Mr & Mrs World Champion pic.twitter.com/AVXdZNNyt4-- Nico Rosberg (@nico_rosberg) November 27, 2016
"I'm really happy and I'm tearing up, this happens every time one of my guys wins. I cried also when Hamilton won the first, the second and the third title.
"Rosberg and Hamilton are like sons for me, and today is really special ... because this is the first title of Nico Rosberg."