The Tigers travel to Bath on Tuesday night needing victory to catapult them back into the Guinness Premiership play-offs.
Already out of the Heineken Cup, Saturday's 23-6 defeat by the Ospreys in the EDF Energy Cup final has left last season's double winners on the brink of failure.
They have just four games remaining to rescue their season and Deacon has left little doubt what is required over the next month.
"Every game is big but they are bigger now. All or games are winnable and we must win them all," he said.
"We were going for the treble last season and now we could end up with nothing.
"When you're as successful as Leicester, everyone is gunning for you.
"Losing to the Ospreys was a massive kick up the backside but we have a great squad and we can beat anyone on our day.
"The frustrating thing is our inconsistency. We were brilliant in the semi-final against Wasps but we didn't do it on Saturday.
"Every team can have an off day but you can't afford to do it in a cup final."
The clash with old foes Bath marks a busy spell for Leicester who will be playing the second match of three in eight days.
Coach Marcelo Loffreda has rung the changes accordingly, handing Ben Kay the captaincy with the England second row the only survivor from the Twickenham horror show.
Former Springbok fly-half Butch James returns for Bath after nearly three months on the sidelines with a shoulder dislocation.
The west country club, who sit in third place and are targeting a top-two finish to secure home advantage in the play-offs, are refusing to take any comfort from Leicester's weakened line-up.
"Marcelo Loffreda joined Leicester after the World Cup and has installed a completely different style of play to that of Pat Howard before him," said forwards coach Mark Bakewell.
"Their style is now more like that of Argentina, which is very confrontational and very direct with a large emphasis on their kicking game.
"Irrespective of what team Leicester field you know that, given the depth of their squad and the strength of their players, it's always going to be a difficult game and a massive battle."