Ryan Giggs marked his 900th appearance for Manchester United with a stoppage-time winner as valiant Norwich were beaten 2-1 at Carrow Road.
Paul Scholes had given the visitors an early lead with a close-range header. The Canaries rallied and forced David de Gea into a string of fine saves before the United number one was finally beaten with seven minutes left when Holt fired home from 12 yards.
United, though, poured forwards in the closing stages and were eventually rewarded when Giggs stabbed home from close range before celebrating in front of the travelling fans.
The champions went ahead after seven minutes when Nani swung the ball over from the right, and it bounced through the six-yard box to the far post, where Scholes nodded it past John Ruddy.
It was almost 2-0 in the 15th minute when another flowing United counter opened up the Norwich defence before Danny Welbeck's scuffed shot was touched wide at full stretch by Ruddy.
Norwich finally created a meaningful chance after 28 minutes, with De Gea having to make a fine reaction save at his near post to deny Anthony Pilkington.
De Gea was producing a top-drawer display as he plucked a glancing header from Holt out of the air.
Giggs was denied a goal when his close-range volley cannoned off the top of the crossbar from Phil Jones' cross after 72 minutes.
Holt squirmed between two markers before firing in his 10th league goal of the season in the 83rd minute.
Ashley Young's goalbound effort was blocked and Welbeck somehow missed a free-header from two yards out but Giggs ensured a fairytale finish when he stabbed home to keep United on the tails of leaders Manchester City.