Beating Buckland Athletic and Exmouth Town and holding Newport County had been one thing for Torquay United in their opening pre-season friendlies, but League One Plymouth Argyle were entirely another matter.
The Pilgrims underlined the two-division gap on the Gulls in emphatic style in front of a 2,500 crowd at Plainmoor.
Argyle were 2-0 up in 20 minutes, with sweet strikes by Finn Azzaz and Danny Mayor.
Former Gulls loanee Adam Randell, who gave a cultured display in the visitors' midfield, made it 3-0 on the stroke of half-time.
Sub Jack Endacott (55mins) and Mayor again (57) slipped Plymouth into cruise-control in a second half in which both sides made a succession of changes.
The Gulls unveiled their eleventh senior signing of the summer before kick-off - 20-year-old Stoke City forward Will Goodwin on loan until January.
But Johnson stuck with the same side which started Saturday's 0-0 draw with Newport County, while Argyle boss Steven Schumacher fielded a more experimental line-up - but with a formidable looking 'bench'.
United nearly took an early lead when Plymouth captain Dan Scarr hauled down Aaron Jarvis just outside the area - surely a booking in a league game - and it took a top-drawer save by Michael Cooper to tip Brett McGavin's free-kick over the bar.
But moments later, in the sixth minute, Azzaz gave the visitors the lead with a sweetly-struck 25-yard shot into the bottom left-hand corner…0-1.
There wasn't much that Mark Halstead could have done about that one, and United had to work hard to stay with Argyle's quick passing counter attacks.
An 'after you' moment in the Plymouth defence gave Corie Andrews a chance, but the ball went just wide.
United thought they had equalised when Ross Marshall headed in a McGavin free-kick, and the offside decision must have been a tight one.
But, in a near repeat of the first goal, United were caught out on the break seconds later, and this time it was Mayor cutting in from the left, United retreating, before firing into the bottom right-hand corner…0-2.
Torquay still had their moments - a strong run and cross by Keiron Evans was pushed out by Cooper and Jarvis could not adjust in time to score - but Argyle's threat was clear to see, and they made it count again just before half-time.
Mayor went close and Halstead saved well from Randell, but when Randell gets his tail up, look out - in stoppage-time he took a pass from Mayor and whipped a right-foot shot into the bottom right corner…0-3.
Johnson sent on new boy Goodwin for Andrews at the interval, and he was unlucky not to score when Cooper somehow kept out his close-range stab from Moxey's cross.
But United's defence could still not cope with Argyle's attacking play, and it showed with two more goals in two minutes.
First, Halstead parried from Mayor and sub Endacott was there to finish…0-4.
Then, it was Ennis who forced another Halstead block and this time Mayor pounced…0-5.
Goodwin, looking lively, tested Cooper with a run and shot, before Johnson sent on Rhys Lovett for Halstead and ex-Plymouth defender Ollie Tomlinson for Marshall.
But it was a bit ominous when, at the same time, Argyle made eight changes, including the introduction of first-teamers Luke Jephcott, Ryan Hardie, Panutche Camara and Joe Edwards.
As it happened, they did not make the night any worse for United.
On the contrary, Goodwin was the bright spark of the night for Torquay.
Although Lovett had to pull out two acrobatic, full-length saves to stop Hardie scoring twice more, Goodwin's pace and eye for an opening visibly sparked the home attack.
At least twice he was unlucky not to grab a consolation goal, lifting Gulls fans who kept up their support in admirable fashion.
By a Special Correspondent
Torquay United manager Gary Johnson admits that his new-look squad needs to improve on its performance in a 5-0 friendly defeat by League One Plymouth Argyle, but he remains confident that they will do just that before the season proper starts at home to Oldham Athletic on August 6.
The Pilgrims scored all their goals in the first hour, through Finn Azzaz, Danny Mayor (2), Adam Randell and Jack Endacott, before sending on several of their usual first-teamers.
But the Gulls, with their latest signing Will Goodwin on loan from Stoke City impressing in the second half, were unlucky not to score at least twice.
"We always knew it would be a tough test, against a team that nearly got into the Championship last season, and I'm sure will do well again," said Johnson.
"We are better than that, we can be better than that and we will be better than that.
"We're not 'oven-ready', as it were. But we've got three weeks to get ourselves ready.
"We learned a lesson today - we'll keep that in our book, and the players will learn from it.
"I was really pleased with a couple of performances - they know who they are. Some have got to do a little bit more for us, and they've got it in them.
"Credit to our supporters, thanks to them - they kept us going.
"Will Goodwin showed people what he's got - he's a strong lad and quick.
"I think everybody will have been quite impressed with the little cameo he had - he looks the player we knew we were bringing in.
"I want to see a little bit more than what we showed today, and we'll talk to the lads about how we do that."
United next meet Exeter City, just promoted to League One, at Plainmoor on Saturday (3pm).
Torquay United (3-5-2): Halstead (Lovett 70); Marshall (Tomlinson 70), Omar, Moxey; Crowe, Donnellan, Hanson, McGavin, Evans (Winsor 75); Andrews, Jarvis (Thomas 80).
Plymouth Argyle (4-3-3): Cooper; Mumba, Scarr, Craske, Gillespie; Butcher, Randell, Miller; Ennis, Azzaz, Mayor.
Referee: Savvas Yianni (Weston-super-Mare).
Attendance: 2,511 (982 Argyle fans).
Torbay Weekly Newsletter
Join the newsletter to receive the latest updates in your inbox.