Brendan Rodgers named a somewhat stronger side than usual in the Europa League, with first-team regulars Pepe Reina, Joe Allen, Fabio Borini and Glen Johnson all involved from the start and Steven Gerrard and Luis Suarez amongst the substitutes.
Liverpool dominated much of the first half and Jonjo Shelvey deservedly put the Reds ahead, but Antonio Di Natale's equaliser less than a minute after the break put the brakes on a dominant display.
Two quickfire goals midway through the half put Udinese 3-1 up as Seb Coates headed an own goal and Gio Pasquale smashed in a third, before Suarez's sublime free kick pulled one back.
It wasn't enough for the Reds and they will need to take points from the upcoming double-header with Anzhi to have a good chance of progressing.
Here are the player ratings for Liverpool.