Albion lead Coventry by two goals to nil after a debut strike from record signing Jurgen Locadia as the Seagulls edge toward the FA Cup quarter finals.
Connor Goldson put the Seagulls two up from an Anthony Knockaert corner on 34 minutes.
Locadia hit the crossbar on the five-minute mark then from a low Knockaert cross put the Seagulls in front with 15 minutes gone.
The League 2 visitors to the Amex are not giving up without a fight though.
Jonson Clarke-Harris hit the underside of the bar for the Sky Blues in a rare attack.
Leo Ulloa and Locadia have linked up well and the latter could have had a couple more.
Krul picked up a facial injury in the first half but carried on. Third choice Nikki Maenpaa has constantly warmed up though.
Victory would mean that Brighton had made it through to the sixth round – the quarter finals – for the first time since 1986.