Marsh-Brown climbed off the bench to score on his debut and secure a vital win for the Bees, who are now unbeaten in four and have not conceded a goal since mid-March.
"The defence was definitely put to the test because the pitch was horrible and they gave us a good fight, they were solid," said Davids.
"Keanu Marsh-Brown is a young talent, he did very well and if you practise well then you play well. It is important when you come off the bench that you show the coach that you are worth playing for the first team and he did.
"I'm delighted for the four clean sheets but I am all about progress. The last couple of games we didn't play that well so we definitely have to work on certain aspects."