Juventus coach Claudio Ranieri admitted Udinese had been the better team and deserved all three points after his side lost 2-1 in Turin.
The Turin giants saw their two-month unbeaten run come to an end in Friuli as the hosts celebrated their first victory since October.
"We wanted to do well," said Ranieri. "But we made mistakes and Udinese played a perfect game. Our opponents showed more determination than we did."
Juve were 2-0 down midway through the second half, and although Vincenzo Iaquinta reduced the deficit from the penalty spot with 13 minutes remaining, Juve were unable to find an equaliser.
"We tried in the second half to put more pressure on Udinese but we created little," admitted Ranieri. "My players showed signs of tiredness."
The outcome in Udine allowed Inter Milan to extend their lead at the top of the Serie A standings to six points over second-place Juve after their 2-0 triumph at Catania.
"We will try again to reduce that deficit," said a disappointed Ranieri.
Juve host Cagliari on Saturday while Inter entertain Torino at the San Siro this weekend.