The Seagulls are nine points adrift of the play-off places and only five above the relegation zone after a run of four matches - two defeats and two draws - without a win.
Monday's visit of Sky Bet Championship promotion hopefuls Watford, seven points better off, gives them a chance to start making inroads into that gap.
"We have to prove it on the pitch but everything is still in our hands," Kuszczak told the club's official website.
"If we start to perform the way we should and the way we are able to, then why not?
"Obviously this season is much harder than last season because of the injuries (Kazenga LuaLua, Liam Bridcutt, Andrea Orlandi, Will Hoskins, Craig Mackail-Smith, Kemy Agustien and Leonardo Ulloa are all sidelined) but there's still a lot of games to play.
"Now we have to put in the hard work and keep winning.
"Defensively I think we've played quite well, we're solid at the back and we have a lot of experience, but football is about goals and we need to do better with this.
"We defend like a team, but without scoring we're not going to win games."
Defence is also an area of concern for Watford after shipping three in the home defeat to Derby last weekend.
"We've been working on defending a lot better as a team; we've gone back to basics," Lloyd Doyley told Hornets Player.
"Concentration is a state of mind; it's all mental really.
"We're all good players here at Watford, we all know how to defend, it's just we need to make sure we concentrate for the whole 90 minutes, and if we do that we know we've got a good enough team to win most games.
"Sometimes you win and sometimes you lose, but what we're trying to do here is be a bit more consistent so that we can win more often than not."