Saints dominated rugby league's famous knockout competition from the outset of Super League, winning it seven times in the first 13 years, but they have endured a lean spell in recent times. Their last Wembley triumph was in 2008 and last year's quarter-final defeat by Wigan ended a run of 11 consecutive appearances in the last four.
Drawn away to Super League rivals Hull KR in Saturday's televised fourth-round tie, St Helens are in serious danger of suffering their first opening-round defeat since losing to Wigan after a replay in 1995. And Howarth said: "It's a massive game."
Decimated by injury, Nathan Brown's men enter the cup in indifferent league form, with three defeats in their last four matches, including a 22-14 loss to KR at Craven Park less than a fortnight ago.
Howarth, who has played in each of the last four games after joining Saints on loan from Salford, says the players' immediate focus is to produce a response after last Friday's 22-12 home defeat by Catalan Dragons.
"The lads were disappointed with what we tossed up at the weekend," he added.
"We're a good team and it was a winnable game.
"We all put our hands up and said it wasn't good enough. I'm sure we will turn it around on Saturday.
"When it got drawn out of the hat, a lot of the lads were rubbing their hands together.
"We want to go back and not let them do that to us again. If we play like we can, we'll win."