Hull stunned Liverpool 2-0 at the KCOM Stadium on Saturday, days after claiming a point at against Manchester United at Old Trafford.
Silva said: "Of course I'm happy with our performance - my team showed a fantastic attitude and fantastic spirit, and the important thing is to keep focus and continue to take more points.
"We need to keep sight of our goal because we have only won three points and nothing more. But this shows the players that this is the right way and they can believe. This is important because when the players don't believe it is impossible."
New boys N'Diaye and Kamil Grosicki played a significant part in the Tigers' success and Silva admitted he had handed the pair their full debuts earlier than he might have wished.
They took their places in the starting line-up four days after completing deadline day deals along with Italian Andrea Ranocchia, who was only upgraded from the bench after Michael Dawson sustained a calf injury in the warm-up.
Silva added: "I would have preferred to give our new signings more time to work with the team but we didn't have the time.
"N'Diaye and Grosicki only worked with me for two days and normally I wouldn't put them in the first 11, but we need these players to improve our squad. Of course I know that in the next games they will improve like all the other players."
PLAYER RATINGSHULL CITYEldin Jakupovic 7Omar Elabdellaoui 6Harry Maguire 7Andrea Ranocchia 9Andy Robertson 6Kamil Grosicki 7Tom Huddlestone 8Alfred N'Diaye 8Sam Clucas 6Evandro 6Abel Hernandez 7Subs: Josh Tymon 6 (for Evandro, 62 minutes); Oumar Niasse 7 (for Hernandez, 65 minutes); David Meyler 6 (for Grosicki, 79 minutes)
LIVERPOOLSimon Mignolet 6Nathaniel Clyne 6Joel Matip 6Lucas Leiva 6James Milner 6Jordan Henderson 6Emre Can 6Adam Lallana 7Sadio Mane 6Roberto Firmino 7Philippe Coutinho 6Subs: Daniel Sturridge 5 (for Can, 67 minutes); Divock Origi 5 (for Lallana, 82 minutes); Alberto Moreno 5 (for Milner (82 minutes)