Scotland launched a second-half fightback against USA as they recovered from a 6-13 deficit to win 39-16 with a bonus-point at Elland Road on Sunday.
It was a match of two halves as Vern Cotter's charges, who were well off the pace in the opening 40 minutes, found their form as they moved top of Pool B.
After the break they clicked into gear with tries from Tim Visser, Sean Maitland, Willem Nel, Matt Scott and Duncan Weir seeing them pick up the maximum.
One negative for Scotland however would have been the sight of Finn Russell being helped off the field with what looked like an ankle injury on 60 minutes.
Scotland came into the game knowing they could take a three-point lead in Pool B after Samoa joined South Africa in having one defeat from two. However, claiming that bonus-point victory was never going to be an easy task as USA have improved a great deal in the past year under head coach Mike Tolkin.
The Eagles going in at the interval 6-13 up certainly proved that point.
It took the Scots until the fifteen minute mark to enjoy their first real period of dominance in the USA half, this after Eagles number ten AJ MacGinty and opposing full-back Stuart Hogg had traded shots. Those offences were for offside and a scrum penalty respectively in an even start.
What was concerning for the USA was a wobbly line-out with hooker Phil Thiel's first two throws being skew before the team's third went loose. Scotland made them pay with the resulting territory and possession as fly-half Russell landed their second penalty of the match for 6-3.
The tide turned in the 21st minute however when from a smart line-out move that saw Samu Manoa standing at inside centre for the carry, USA's recycled ball saw tighthead prop Titi Lamositele picking and driving over for the game's first try. With MacGinty's extras the Eagles were 6-10 up.
Scotland had their chance to respond in quick time but it was butchered on a seismic scale. Hogg's electric feet saw him run from his own ten-metre line down to the USA 22 but his final pass to Visser was poor and the left wing could not hold it. Elland Road could not believe it.
Things would not improve from a Scottish point of view before the break as Russell's missed 40 metre penalty attempt preceded yet more errors, with USA's physical gameplan clearly having rattled their opponents – Takudzwa Ngwenya's huge blindside tackle on Peter Horne helped with that.
As mentioned, USA would jog into the dressing rooms 6-13 to the good after Scotland came offside in their 22, MacGinty slotting the easy penalty.
Scotland were sure to have been given the hairdryer treatment from head coach Cotter, who brought on props Alasdair Dickinson and Nel. It paid immediate dividends on 42 minutes when Hogg this time found his wing Visser for a clear run-in down the left. That made it 11-13.
The wheels were now in motion for Scotland and when Russell made up for his missed conversion of Visser's try with a cool assist for Maitland, his extra two points this time meant USA were now behind 18-13. Fortunately for the States, a MacGinty penalty cut that down to 18-16 and halted the onslaught.
It was short-lived as replacement Nel powered over from close range and with Greig Laidlaw, on for Henry Pyrgos, adding the two, Scotland were 25-16 up and for the first time in the game had a cushion. Now they could focus on getting the bonus point that for so long looked unreachable.
They would have to achieve it minus fly-half Russell though after his withdrawal, but his replacement, Weir, and Scotland had 20 minutes to get the job done. And so started a period of sustained pressure in the USA 22, with referee Chris Pollock losing patience with the Eagles.
USA's defence expectedly crumbled as Scotland had that pivotal fourth try thanks to a lovely line from replacement centre Scott before Weir added the fifth as Cotter's men head to Newcastle to face South Africa next Saturday full of confidence.
Man of the match: While his opposite number Phil Thiel had a difficult game with his throwing, Ross Ford was solid and put in a shift for his team. Originally set to be on the bench before injury hit John Hardie, Ford had a strong 78 minutes for Scotland.
Moment of the match: Whatever was said in the dressing room at half-time clearly did the job. Vern Cotter take a bow.
Villain of the match: Yet another World Cup match played in good spirit as neither side felt the wrath of Chris Pollock.
Tries: Visser, Maitland, Nel, Scott, Weir
Con: Russell, Laidlaw 3
Pen: Hogg, Russell
Pen: MacGinty 3
Scotland: 15 Stuart Hogg, 14 Sean Maitland, 13 Mark Bennett, 12 Peter Horne, 11 Tim Visser, 10 Finn Russell, 9 Henry Pyrgos (c), 8 Josh Strauss, 7 Ryan Wilson, 6 Alasdair Strokosch, 5 Richie Gray, 4 Grant Gilchrist, 3 Jon Welsh, 2 Ross Ford, 1 Ryan Grant.
Replacements: 16 Kevin Bryce, 17 Alasdair Dickinson, 18 Willem Nel, 19 Tim Swinson, 20 Fraser Brown, 21 Greig Laidlaw, 22 Duncan Weir, 23 Matt Scott.
USA: 15 Chris Wyles (c), 14 Takudzwa Ngwenya, 13 Seamus Kelly, 12 Thretton Palamo, 11 Blaine Scully, 10 AJ MacGinty, 9 Mike Petri, 8 Samu Manoa, 7 Andrew Durutalo, 6 Al McFarland, 5 Greg Peterson, 4 Hayden Smith, 3 Titi Lamositele, 2 Phil Thiel, 1 Eric Fry.
Replacements: 16 Zach Fenoglio, 17 Oli Kilifi, 18 Chris Baumann, 19 Cam Dolan, 20. John Quill, 21 Danny Barrett, 22 Shalom Suniula, 23 Folau Niua.
Referee: Chris Pollock (New Zealand)
Assistant referees: John Lacey (Ireland), Mike Fraser (New Zealand)
Television match official: Ben Skeen (New Zealand)
by Adam Kyriacou at Elland Road