The visitors were content to soak up the early pressure, but debutant Oliver Antman’s pace soon had Plzen on the back foot, and he almost delivered the perfect cross for Djeidi Gassama to head home after 10 minutes.
It was a warning that Plzeň failed to heed, and a superb piece of inventive play from Gassama four minutes later saw him take three opponents out of the match with one pass.
Cyriel Dessers invitingly offered up the chance for a one-two, and the former didn’t need asking twice, as he swept in to bend home the opener past 6ft 9in Plzen keeper, Florian Wiegele.
Plzeň nearly made the perfect response, as Matej Vydra shaped up to fire home an equaliser, only to see his effort brilliantly blocked by Nasser Djiga.
But Plzen were reduced to hitting hopeful balls as the first-half wore on – a contrast from the dual threat of Dessers and Antman, the latter of whom went on a surging run shortly before the interval, tempting Vydra into nudging him from behind.
Referee Clement Turpin had no option other than to award a spot-kick. Dessers took the responsibility and sent Wiegele the wrong way with a confident dispatch.
Mohamed Diomande’s curling and looping effort from the edge of the box on 48’ agonisingly came back off the bar as Rangers began the second half as they’d ended the first. And just two minutes later, Antman was again involved thanks to a pinpoint cross that was deftly headed home by Gassama.
With more than half an hour to play, Plzen already looked a beaten side, though Martin brought on Nicolas Raskin for Joe Rothwell in order to freshen up a Rangers side that understandably took their foot off the pedal after the third goal.
As the game entered the final stages, scrappy play from both teams earned a broadside from their respective managers before Rangers upped the tempo once more with 10 minutes to play.
Amar Memic took aim from way out, and though his shot was on target, Jack Butland simply swatted it aside to keep his clean sheet intact. Still very much full of energy, Gassama almost prodded home his hat-trick goal immediately afterwards, before being subbed alongside Antman to a standing ovation.
The result means Rangers made it four games undefeated against Czech sides (W3 D1), and Plzeň’s first defeat against a Scottish side in European competition is one they won’t forget in a hurry.
As UCL history shows, nothing is impossible – but the men from western Czechia undeniably have a mountain to climb in the return leg.
Flashscore Man of the Match: Djeidi Gassama (Rangers)