St Helens coach Justin Holbrook was delighted after his side saw out a closer than expected encounter at Huddersfield despite never displaying the customary Saints sparkle.
Saints edged a see-saw encounter 22-16 to earn a home Coral Challenge Cup quarter-final tie against Wakefield.
Holbrook was relieved his players held on as they chase a place in the final at Wembley.
He said: "It was a tough game. We're happy to get the win but that's what the Challenge Cup does - everyone wants to get to Wembley.
"The ruck was the slowest I've ever seen which makes it hard work. The pleasing thing was that, although we couldn't finish them off and were only six points ahead, we controlled the game.
"Even though the game was tight, we were still in control and didn't need to panic and come up with something special.
"In the end, it's just about being confident and backing ourselves to play the way we want to.
"The beauty about this comp is that anyone can win on the day - you don't have to be consistent throughout the year and Catalans (who won the trophy) proved that last year.
"Wakefield is a tricky game, like today, and they are always capable of playing really well and testing any side in the competition."
Saints were three times forced to forge a lead before finally shaking off a dogged Giants side who were never more than a converted try behind and led 10-6 after half an hour.
Joe Wardle and Aaron Murphy scored for the hosts before the break with replies from Regan Grace and Theo Fages helping the Merseysiders to a 12-10 half-time advantage.
A try from Lachlan Coote, who also kicked three goals from six attempts, increased Saints' advantage following the restart, only for Wardle's second touchdown and former Saint Lee Gaskell's second goal to help the Giants draw level.
But Kevin Naiqama dived over just after the hour and despite Coote missing a drop goal attempt, St Helens held on to progress to the last eight of the competition.
Huddersfield coach Simon Woolford was pleased with his side's performance.
He said: "I thought we were fantastic in most areas - our goal line D (defence) was great.
"We came up short defending some of their kicks and also sometimes with the ball but there have been a lot of games where we've lost and I haven't felt like this.
"We took a giant step forward - we've got a couple of players back and get a couple more next week, so we are happy with our effort and I thought we deserved more.
"Our defence did enough to win the game and if we had been better with the ball we might have broken them but we weren't."