Scotland kept their hopes of a World Cup quarter-final spot alive with a 22-8 victory against the USA in Salford.
Tries from Kristian Freed and Taylor Welch gave the USA an eight-point lead, but Scotland responded with three scores in 12 minutes after the break.
Brett Phillips, Matty Russell and Luke Douglas all went over, before Alex Hurst made the game safe.
Despite the win, Scotland will only progress to the last eight if Italy fail to beat Tonga on Sunday.
With the two sides level on points difference, the Azzurri are certain to top Group C if they are successful in Halifax.
The Bravehearts had already surpassed their best-ever performance at a World Cup even before Thursday's success, but an unbeaten record in their group still may not be enough for them to feature in the knockout stages.
If they do qualify, it is unlikely that Ben Fisher will be able to participate in a potential quarter-final against holders New Zealand. The London Broncos hooker, who has announced he will retire at the end of the tournament, was injured in the warm-up and appeared in an emotional state as he was helped from the field by Scotland's medical staff.
Terry Matterson's USA, playing in their first World Cup, went into their inter-group encounter at the AJ Bell Stadium with the luxury of knowing their spot in the last eight and a probable tie with tournament favourites Australia was already secure.
The Tomahawks had the better of the opening exchanges and broke the deadlock when a flat pass from half-back Joseph Paulo, so influential in their earlier victories against the Cook Islands and Wales, picked out Freed.
The full-back dived over from close range, although he and his team-mates appeared somewhat surprised when the try was eventually awarded by video referee Henry Perenara.
Scotland almost responded straight from the restart but they were twice denied, as first centre Ben Hellewell was held up over the whitewash and then Hurst's effort was ruled out for a forward pass.
Their desperation to get back on terms showed when Dale Ferguson was penalised for a dangerous tackle and put on report by on-field official Thierry Alibert, while their frustration grew further when centre Welch touched down Craig Priestly's grubber kick to extend the Americans' advantage.
Scotland needed some inspiration and their reliable half-back partnership almost provided it, as Peter Wallace and Danny Brough combined for skipper Brough to cross under the posts, only for Perenara to intervene again and judge that the Scots had been guilty of obstruction during the build-up.
They finally registered their first points shortly after the interval when second-rower Phillips collected Brough's pass to score, and when Brough - Super League's Man of Steel - converted Russell's try from a darting run two minutes later, Scotland were suddenly two points in front.
Opposing wingers Hurst - playing in his home-town stadium - and Matthew Petersen both spurned opportunities before a powerful effort from forward Douglas just past the hour mark sent Scotland further clear.
Hurst's late try, again set up by Brough, sealed victory during a fractious conclusion to the game, and they now face an anxious wait before their World Cup fate is decided.
Scotland: Russell; Hurst, Hellewell, Addy, Scott; Brough, Wallace; Walker, A. Henderson, Douglas, Phillips, Ferguson, Kavanagh. Replacements: Barlow, Szostak, Stringer, Wilkes.
USA: Freed; Faraimo, Welch, Garvey, Petersen; Paulo, Priestly; Offerdahl, Samoa, Pettybourne, Newton, Shipway, Howard. Replacements: Marando, Hifo, Luani, Lavulo.
Referee: Thierry Alibert (France)