It was a more forgettable debut for goalkeeper Harry Burgoyne, whose errors for two Boro goals proved costly for Salop - who led but found themselves 3-1 and 4-2 down.
But there was a first sign of Sam Ricketts’ more open, attack-minded and expressive side as Town fought bravely in their first competitive fixture for almost six months. Jason Cummings netted their second before Pyke’s smart finish brought them back to 4-3 but there was to be no grandstand finish.
Huddersfield loanee High lit up the tie early on with a fabulous opener from distance on his first senior start in front of empty stands at the Riverside Stadium and the goals flowed all evening.
Aaron Pierre was the surprising omission from Ricketts’ XI on Teesside, as Ro-Shaun Williams partnered Ethan Ebanks-Landell in the back four. Burgoyne, having signed in January, made his debut in goal.
With Ollie Norburn injured and Josh Vela suspended, Sean Goss also had to settle for a place on the bench as Brad Walker was given the nod in midfield alongside High and Dave Edwards.
Town lined up in their new 4-3-3 shape for the forthcoming season, Cummings on the right, and Shaun Whalley on the left, flankling another blue and amber debutant, striker Pyke.
Daniel Udoh was on the bench, as was loan defender from Fulham Marlon Fossey and new winger Josh Daniels.
Boro, guided by Neil Warnock to 17th in the Championship after the second tier resumed earlier in the summer, named a strong side for the tie.
They have lost no fewer than nine senior players - including last season’s loanees - in the close season, and only added defender Grant Hall from QPR.
But Warnock’s side was still packed with Championship and top flight experience, including dangermen Britt Assombalonga and Ashley Fletcher as a potent forward pairing.
The 34,000 capacity Riverside Stadium, where Shrewsbury had not visited since an EFL Trophy tie in November 2016, was totally empty and an eerie setting as Ricketts’ men prepared for their first challenge in the new normal.
Boro had the experience of Championship action at the back end of last season to call upon.
All players took the knee in support of the Black Lives Matter movement on the referee’s whistle, you could hear a pin drop in the empty arena in an environment that will doubtless take some getting used to for Salop.
The hosts began brightly but signs of the new shape working well appeared as Town forced Boro long and combined well with crisp interchange.
There was little sign of any goal threat at either end by the time the tie was lit up after 13 minutes.
Whalley darted infield from the left and played a square pass to High, who was 25 yards out to the right of the D.
The young Terrier, who scored a fine volley at Burnley a week earlier, steadied himself because unleashing a rocket that arrowed into the far top left corner. The strike whistled beyond hapless keeper Dejan Stojanovic who was a spectator.
It was a crying shame there was nobody here to witness the debut wondergoal.
Shrews had Boro on the ropes as Pyke muscled through to stab a Cummings cross from the right just over the angle of post and bar.
The visitors were impressing but, on 21 minutes, undone on a moment to forget for Burgoyne.
Boro worked some space down the right and Lewis Wing’s delivery to the back post found the unmarked Johnson whose volley was straight at Town’s keeper but the effort squirmed through Burgoyne and deflected into his net despite Ebanks-Landell’s efforts to keep it out.
The visitors responded well to the sucker punch and went close after a fine left-sided cross from Edwards but Middlesbrough edged ahead after half hour.
Johnson, playing at left wing-back, again had too much room and his good low cross was well turned in by Fletcher from six yards out.
Town continued to hold their own after the break. A brilliant Walker volleyed pass released Cummings on the right. His shot was blocked and cries for handball were ignored.
No danger was apparent when a Boro long ball had Burgoyne creeping out his box towards the right corner flag.
But the keeper’s clearance was scuffed and weak and fell to a red shirt. Marcus Tavernier squared to Wing whose low 30-yard strike was tipped on to the post by the retreating Burgoyne before Fletcher scuffed the rebound over the keeper and in. Offside calls were waved away.
Burgoyne appeared disconsolate on his Shrewsbury bow. Team-mates attempted to gee him up.
To their credit, Ricketts’ men rallied. Pyke, who had impressed, muscled his defender out of it to go clear on goal but sent his big chance wide.
The ex-Wrexham man then strongly turned his defender in the box but his shot was deflected wide.
Cummings was alive to the resulting corner at the far post and worked an angle on his left foot and curled in a stunning finish to halve the deficit on the hour.
But five minutes later and Tavernier profited from a half-cleared free-kick, striking low into the corner via an unfortunate deflection.
You could not take your eyes off the roller-coaster contest. With 18 minutes left, Scott Golbourne worked room in the box and picked out Pyke with a delightful through ball and the debutant pounced from close range.
Salop sniffed blood in the roller-coaster contest. Daniel Udoh and Josh Daniels were sent on by Ricketts. Cummings was sent free and decided not to square to the unmarked Udoh and his shot was blocked.
The tie swung this way and that. Assombalonga shot low at Burgoyne but Salop pressed for a remarkable equaliser.
With two minutes left Udoh turned well but his low shot was well saved by Stojanovic before Burgoyne denied Marcus Browne as Boro just about squeezed into round two.
Stojanovic; Dijksteel, Hall, Fry (Wood, 74); Spence, Howson, Wing (Browne, 73), Tavernier, Johnson; Fletcher, Assombalonga.
Subs: Pears, Bola, Stubbs, Folarin, Walker.
Shrewsbury Town (4-3-3):
Burgoyne; Love (Fossey, 82), Williams, Ebanks-Landell, Golbourne; Walker, High, Edwards (Daniels, 75); Cummings, Pyke (Udoh, 75), Whalley.
Subs: Gregory (gk), Pierre, Goss, Barnett.
Referee: Michael Salisbury