Kyle Steyn became the first Scotland player to score four tries in a match for 26 years as Gregor Townsend's side opened their autumn series with a 10-try defeat of Tonga.

David Lolohea's score for Tonga came while the hosts were down to 14 men with Rob Harley's sin-binning and the tourists' Aisea Halo was also yellow carded.

Steyn, in his first international start, emulated Gavin Hastings' four scores against Ivory Coast at the 1995 World Cup.

Luke Crosbie, Ross Thompson, Marshall Sykes and Jamie Dobie came off the bench to follow McLean, Schoeman, Sione Tuipulotu and Jamie Hodgson in debuting for the Scots, who were playing in front of a Murrayfield crowd for the first time in 19 months.

Townsend's side will host Australia, South Africa and Japan over the next three weekends, with England and France-based players becoming available for those matches.

Pity Tonga. It was a rout. Not quite as excruciating as the 100-pointer they suffered at the hands of the All Blacks in the summer, but painful nonetheless. Quite honestly, they did not really stand a chance.

They had no answer to McLean's fast feet, no answer to Steyn's excellent finishing and no resistance as Scotland poured it on.

To be fair, this was not the team that did so admirably at the World Cup two years ago; the promising gang that gave England and Argentina a decent game, that took France to the wire and only lost by two points before putting the USA away comfortably.

There were less than a handful of survivors from that team this time around and, of course, none at all from their seismic win over the Scots in Aberdeen in 2012.

What does not change is their physicality and overwhelming desire to annihilate people in the tackle. They did a bit of that earlier on - Darcy Graham got a couple of dunts from their heavy mob - but every time Scotland got into vaguely threatening territory they scored. They were slick but Tonga's defence was like soft butter and only proceeded to melt as the game went on.

Even allowing for the one-sided nature of it all, you had to admire McLean. The 21-year-old's footwork and pace were a joy and way, way too much for Tonga. He looks a total star in the making.

He got his first after Jamie Ritchie had been blasted in the tackle (without the ball, it has to be said). McLean scooped it up, accelerated away, bounced the visiting scrum-half Sonatane Takulua out of his road and scored.

Blair Kinghorn, warming the 10 jersey for Finn Russell, converted. James Faiva made it 7-3 but McLean struck again within minutes. Tonga bit down on more dummies than an agitated child. A lineout, some midfield deception, a floated Kinghorn pass and away McLean went up his left wing, stepping Faiva before motoring on.

Faiva booted over another penalty to slow Scotland's strike rate but it was a temporary resistance. Tonga were undone again in midfield. Tuipulotu drew the cover and gave the pass to Steyn for the first of his four. Steyn, happily restored to full fitness after a terrible run of ill luck, can be a serious operator at this level.

That score made it 19-6 with just 24 minutes on the clock. Once again, Faiva reduced the gap by three with a penalty from distance but everybody knew what was coming next. Tonga made a hash of dealing with the restart and the next time they got it back, they had conceded again. Schoeman landed another score for the debut boys. No McLean-esque gas required. This was a grunt from close range. They all count.

Kinghorn's extras made it 26-9, which quickly became 31-9 after a routine move off a lineout saw Steyn swatting away Vaea Vaea on his way to the posts. Steyn completed his hat-trick before the half was out.

McLean was heavily involved again, breaking loose out of defence before finding Graham on his shoulder. With Tonga spreadeagled, Kinghorn chanced a crossfield kick, which bounced kindly for his winger. Three for Steyn and six for Scotland. The visitors looked like broken men.

Very little of this was relevant to the battles to come in November but it was ruthless all the same. Scotland's seventh came early in the second half when Turner was driven over in a lineout maul. Kinghorn failed to hit the target again with the conversion, three from seven for the fly-half.

Harley's sin-binning gave Tonga the chance to take a modicum of solace from the day and they took it when Lolohea barrelled over.

The game went flat, the crowd became hushed, the try-count dried up for a wee while before Haining and Kebble made it eight and nine tries and with it came the 50-pointer. Then Steyn cut his way through for number 10 - and his fourth. What a day for him.

Everybody then turned their minds to the arrival of the Wallabies and the return of former Glasgow coach, Dave Rennie. This was pleasing stuff for Townsend with the classy McLean and the prolific Steyn the main talkers.

The big stuff of the autumn starts now, though. Next week there will be an altogether different animal in town.

Scotland: Graham, Steyn, Tuipulotu, Johnson, McLean, Kinghorn, Price (co-capt); Schoeman, Turner, Z Fagerson; Hodgson, Harley, Ritchie (co-capt), Watson, M Fagerson.

Replacements: McInally, Bhatti, Kebble, Sykes, Crosbie, Haining, Dobie, Thompson.

Tonga: Faiva, Manu, Hingano, Vaea, W Fifita, Morath, Takulua (captain); Uhila, Ngauamo, Lolohea, H Fifita, Funaki, Halaifonua, Lokotui, Mapapalangi.

Substitutes: Maile, Felemi, Taufa, Faleaf, Havili, Kafatolu, Halo, Haisila.

Referee: Nic Berry.