A flawed start and a worrying amount of possession and opportunity for the Force gave way to a strong win in the end for the Lions.
McCarthy was a compelling force up front as the Lions backline eventually ran amok.
They will sweat on what looked like a hamstring injury for Williams, who had been playing like a thoroughbred.
Jamison Gibson-Park has not yet played for these Lions, although he is expected to be available for midweek in Brisbane. It is a worry for coach Andy Farrell.
The Lions got off to a flyer on the night after a sustained bout of possession when Russell dipped into his box of tricks with a sumptuous cross-kick to Sheehan on the right wing.
Sheehan tapped to James Lowe, who gave it back to his captain for the score. The creator banged over the conversion.
A blistering beginning, but there was trouble ahead. Just as the Lions scored with their first attack, so too did the Force.
Again it was a slow turning of the screw before White sprung from the bottom of a ruck just short the line. Ben Donaldson was good with the conversion.
The Force were heavy underdogs but for 40 minutes they played with a confidence that belied their poor season in Super Rugby. They repeatedly got into the Lions 22 and time and again the tourists got pinged.
The Lions conceded five penalties in 80 minutes against the Pumas in Dublin. They conceded four in 10 minutes in Perth. Sheehan was warned about the ill discipline of his team as early as the 11th minute. This is not how it was supposed to be.
If the Force had been more accurate they would have capitalised on all those entries into the Lions 22.
They won a penalty and went for touch on the right, but nothing came of it. They won another penalty and went for touch on the left, but nothing came of that either.
Credit the tenacity of the Lions defence too, but they were doing much of it. When they got ball in hand, they were the polar opposite of the Force.
It must have been a sickener for the hosts when the visitors lifted the siege in their own territory only to score straight away.
A break from Ireland’s Josh van der Flier, a big bust from England’s Pollock and a support line from Wales’ Williams and over they went. Ruthless. More Force wastefulness followed and soon another Lions try arrived.
Like the first, it was Russell at the root of it, his tap penalty, break and offload putting Daly over. A minor scuffle broke out in the aftermath.
The Force’s angst carried on. Once more they had a close-range lineout – and a one-man advantage after Pollock saw yellow at breakdown – but they could not execute. A 14-point half-time lead for the Lions felt out of kilter with the flow of the game.
It got better, though. A lot better. Even with Pollock in the bin, the Lions struck out for a majestic score from inside their own 22.
Hansen got them moving but it was Lowe and Williams who did a supreme job in pulling the trigger, running and offloading before the scrum-half went over for his second score.
The downside – and it was a significant one – was the injury he picked up in the act of scoring.
It had everyone in the media seats scurrying around determining the whereabouts of Scotland’s Ben White (handily placed in New Zealand) and England’s Jack van Poortvliet (not so handy in Argentina).
As the Force tired, the Lions piled on the heat.
Ringrose went over for try number five after fine work by Hansen, and the combative and impressive McCarthy went over for number six after more terrific work from Pollock. Russell’s conversion brought up the 40-point mark.
Daly completed his double and replacement Mitchell went over in the last act to bring up the half-century.
