Challenge Cup: Castleford Tigers 18-36 St Helens
|Ladbrokes Challenge Cup|
|Castleford Tigers (0) 18|
|Tries: Trueman, Minikin, McMeeken Goals: Ellis 3|
|St Helens (12) 36|
|Tries: Grace, Barba 3, Morgan, Richardson Goals: Richardson 6|
Ben Barba's hat-trick of tries inspired St Helens to victory at Castleford as the Super League leaders reached the Challenge Cup quarter-finals.
Regan Grace and full-back Barba ran the length of the field for Saints' two first-half scores and Barba's second made it 18-0 just after the interval.
Jake Trueman and Greg Minikin replied, but Ryan Morgan and Danny Richardson maintained Saints' healthy lead.
Barba then jinked his way past five defenders to complete his treble.
The 28-year-old, a former NRL player of the year in his native Australia, further enhanced his reputation as the outstanding player in Super League with a man-of-the-match display to lead his team into Sunday's quarter-final draw.
Castleford, who thrashed St Helens 53-10 at the same stage of last season's competition, matched their opponents for most of a physical sixth-round contest.
However, it was Saints who seized control of the tie with two breakaway tries.
Barba's superb offload sent Grace away for the opener, before Barba picked up a loose ball and raced clear himself to establish a 12-point half-time lead.
Castleford were always playing catch-up after that and Mike McMeeken's last-minute score proved only a consolation for the hosts.
St Helens full-back Ben Barba told BBC One:
"That was one tough game. Castleford put up a great fight.
"I say it every week - I'm lucky to play behind such a great forward pack. I just do all of the flashy stuff at the back, but it all comes down to their hard work.
"It's been 10 years since this club has played in the final. We spoke about taking steps and this is step one. The competition is only going to get harder."
Castleford head coach Daryl Powell:
"I just didn't think we were quite durable enough. When Saints put the hammer down, they were too strong for us.
"They're a good side, they've got the best player in the competition at the moment and when he puts his foot down they find some space.
"We gave key penalties away and made poor errors when we looked like we might put a bit of pressure on St Helens."
Castleford: Shenton; Minikin, Webster, Wardle, Hitchcox; Ellis, McShane; Watts, Milner, Sene-Lefao, Holmes, McMeeken, Foster.
Replacements: Moors, Millington, Cook, Trueman.
St Helens: Barba; Makinson, Morgan, Percival, Grace; Lomax, Richardson; Amor, Roby, Thompson, Peyroux, Taia, Wilkin.
Replacements: Fages, McCarthy-Scarsbrook, Douglas, Knowles.
Referee: James Child