Watford boss Tom Cleverley told BBC Three Counties Radio:
"It's not easy playing in these derbies, or preparing for them like they're a normal game because they're not, so to get on the front foot like we did and to have the character to play the way we wanted to was important.
"Mamadou Doumbia has brought chasing lost causes to our team, being willing to run, to stretch defences, maybe he's not had direct assists or goals, but he's having a big part to play in pretty much every goal we're scoring at the minute.
"There's a certain stage where you've got to manage the game and go from front foot to a bit more protective and we maybe did that a little bit too early - but when we did have to manage the game and see out a bit of pressure, we stood up to it.
"Take the local rivalry out of it, it was an important game for us to get three points in, in terms of our league position."
Luton Town manager Matt Bloomfield told BBC Look East:
"The players are obviously extremely disappointed with the result and really disappointed not to give our supporters something to cheer about because they turned up in incredible numbers and backed us.
"For the first five or six minutes I thought we were OK and played in Watford's half, took the sting out of them early on, then we gave the penalty away and the second goal was again loose from us - and at 2-0 down it rocked us, understandably so.
"We made changes at half-time, gave ourselves a foothold and grew back into the game and if we'd turned one of those opportunities into a goal, you never know what will happen from there.
"The boys are still fighting, they still passed, they probed, they still created chances, but we need to take one of those opportunities at 0-0, not 2-0 down."