The 29-year-old watched on as his teammates came from behind to beat West Bromwich Albion 3-2 last weekend to earn three vital points in their quest for survival.
"After watching the game at the start, it was looking a bit grim," Kelly told PA. "But to be able to come back, hold on, and show that kind of character and fight is exactly what you need to stay in the Premier League.
"That win has put us closer to the other teams. You look at the table and think it's not impossible.
"I am confident we can stay up. After coming here and meeting everyone affiliated with the club you realise everyone is determined to stay in the league. The determination is unbelievable."