Martin Jol's side have won only one of their last seven games, slipping to just six points above the relegation zone following Saturday's 2-0 defeat to Manchester City.
|4/1||Fulham are 4/1 with Bet365 to force a replay against Manchester United in the FA Cup
"It's been tough," he told the club's official website. "The Christmas period is always hard with the amount of games. If you can come through it having done well then spirits are always high.
"Coming out of this one, it’s been tough but it's all about team spirit now, digging deep and working for each other.
"You're not going to get results if you don't work hard, that's the first thing you do.
"We've got some big games to come now, starting with United in the cup. It's a break from the league and we need to go up there, not sit back and try and play our football.
"We've then got two hard league games so tricky fixtures are ahead but we look forward to them."