Sir Alex Ferguson was beaming with delight as Anthony Martial slammed home Manchester United's second against Manchester City in the first half.
The Red Devils put on a dazzling performance and caused problems for City when they broke through on the counter-attack.
Marcus Rashford opened the scoring from the spot-kick in the 23rd minute and only six minutes later Martial doubled United's advantage.
And the camera caught the legendary former United manager with a cheeky smile on his face as the young Red Devils side dealt another blow to City's title hopes.
United fans have flocked to Twitter and are buzzing to see Ferguson happy at United's performance.
Rashford came close to scoring his second minutes before Martial found the back of the net.
Daniel James found the 22-year-old United striker on the edge of the area and Rashford's effort hit the woodwork.
United lead 2-0 at the Etihad going into half-time.
Full-time result: Manchester United have beaten Manchester City 2-1. Nicolas Otamendi pulled one back for the defending Premier League champions in the second half. But United managed to hold on and secure all three points.
Featured Image Credit: Sky SportsTopics: Manchester City, Football News, Anthony Martial, Etihad Stadium, Football, Manchester United, Sir Alex Ferguson, Marcus Rashford