Luton reached the fifth round of the FA Cup for the first time in nine years with a 3-0 success at Cambridge.
There are 29 places between the sides and goals in the first quarter of the game from Reece Burke and Carlos Mendes Gomes ensured there was rarely much likelihood of League One Cambridge springing a surprise for the second successive round.
The home side were missing the presence of injured forward Joe Ironside, scorer of the winner in their famous triumph at Newcastle in the third round, as well as influential defender Jack Iredale.