The Glasgow Warriors winger scored four tries, the first Scot to do so in a Test match since Gavin Hastings against Côte d'Ivoire at the 1995 World Cup in South Africa.
Another Glasgow wide man, Rufus McLean, weighed in with a sparkling double on his debut as Gregor Townsend’s side threw the ball around against opponents who never shirked a challenge but looked short of Scotland’s fitness levels.
It wasn’t all about the backs, though. On the day that Scottish rugby paid tribute to the great Sandy Carmichael it was appropriate that a prop also made his mark, with Pierre Schoeman marking his first international appearance with a try.
Second-half scores from George Turner, Nick Haining and Oli Kebble forced home Scotland’s superiority and they will go into next week’s game against Australia in good heart.
Townsend gave eight players their debut and experimented in the back line with Blair Kinghorn at stand-off and Darcy Graham at full-back. Both men adapted well to unaccustomed roles but it was the wingmen who stole the show.
McLean is a man who makes things happen and it took him less than 15 minutes to notch his first two international tries. The build-up to the first was a little messy and there was an inadvertent assist from Ritchie who was on the receiving end of a mighty hit from Tanginoa Halaifonua. The ball broke free off the Scotland flanker and McLean picked it up and burst through two tackles for the score.
Tonga had fatally hesitated, perhaps believing Ritchie had knocked the ball on, but a check with the TMO confirmed the ball had come off the Scotland man’s shoulder and the try stood. Kinghorn converted.
Tonga came straight back and a penalty from James Faiva cut the lead to 7-3, but McLean was in fizzing form and his second try was executed superbly.
A lineout on the right was gathered by Jamie Hodgson and as the ball was moved out Kinghorn floated a delightful pass over the head of Graham to the Glasgow winger who scorched to the line from 20 metres out, stepping inside Faiva on the way. Kinghorn was on target again with the conversion.
Faiva knocked over another penalty for Tonga but Scotland were soon back in the ascendancy and it was time for Steyn to get in on the action. Going one better than his clubmate, Steyn weighed in with a first-half hat-trick as the home side turned the screw.
The first came from a smart backs move as Scotland overloaded the right channel and the ball went through the hands of Price, Kinghorn, Graham and Sione Tuipulotu before Steyn finished off the move.
Faiva’s third penalty did little to dent Scotland’s progress and Pierre Schoeman was able to squeeze over for a debut try - with the help of George Turner - before Steyn could get his second.
Like’s McLean’s second try, Scotland worked the ball from a lineout move on the right, with Watson feeding Price who played in Steyn. The winger did the rest, running through some flimsy defending on the way.
The hat-trick score came on the stroke of half-time and was orchestrated by Kinghorn who seemed to be relishing his outing at stand-off. A cross-field kick from the Edinburgh man bounced favourably for Steyn and there was only one winner as he vied with an out-of-puff David Lolohea to be first to the ball. Kinghorn’s conversion attempt struck the post but Scotland went in at the break 36-9 ahead.
Townsend’s Scotland are anything but one-dimensional and the seventh try came from a lineout drive, straight out of last autumn’s playbook. George Turner finished things off but Kinghorn was off target with the kick at goal, his fourth miss of the day.
Things started to get a little ragged as both sides made a rash of substitutions. The introduction of Jamie Dobie meant Scotland were fielding a player born in 2001 for the first time, usurping another debutant, McLean, who had been the first born in 2000 to pull on the dark blue.
One of the elder statesmen, Rob Harley, was shown a yellow card for repeat infringements and Tonga took advantage by crossing for their first try, Lolohea forcing his way over from close range.
The sides were soon even again after Aisea Halo was sent to the sin-bin for taking out McLean in the air. The Scotland winger felt the full force of the Tongan sub and had to go off. He was replaced by another debutant, lock Marshall Sykes, forcing a reshuffle of the Scottish backs.
Sam Johnson, who had been on the receiving end of a fierce hit five minutes earlier, looked like he was in for a try after a smart behind-the-back offload from Ritchie. The centre was held up just short but Haining was there to pile over for his first international try.
Scotland pressed home their superiority in the final five minutes, scoring two more tries to make it ten for the afternoon. Oli Kebble got the first, taking the ball from the base of the ruck and forcing his way over.
Steyn then rounded off his man-of-the-match performance with his fourth try.
Ross Thompson, on for his first cap, took over kicking duties and converted both late scores.