Bruno Guimaraes struck to earn the Toon a 1-0 victory on Monday night.
Howe said afterwards: "One of our best wins of the season, not in terms of performance but desire and heart.
"All the big ingredients you need to be a successful team. Need to win when the game is tight and find a way to get over the line. We defended really well after the first three minutes which were a bit scary. Deserved win.
"That’s why for me it was such a good win, it would be easy for the players to be distracted but they were present.
"Harvey (Barnes) did very well today. Lovely cross. Tino (Livramento) looked good at left-back.
"We’ll focus fully on Liverpool now. We’ll take everything into consideration.
"I felt we were in need of a win to go into the final with a real boost and lift. Will do us the world of good. Also for our league table position today was vital."
Next up for Newcastle is the Carabao Cup final this coming weekend against Liverpool.
Howe also said: "These games, we learned this last time can be quite a long wait, everyone talking about it but you have massive games ahead. Pleased it's here, hopefully we can perform well."