Martin Hysky may have been missing various players, but his side went ahead just six minutes into proceedings.
Denis Visinsky slid in on Diogo Costa following an underhit Jan Bednarek pass, and Lukas Cerv collected Matej Valenta’s ball before striking from outside the box to beat the Dragoes’ goalkeeper.
Porto couldn’t fully compose themselves in the aftermath, and Christophe Kabongo came agonisingly close to doubling the hosts’ lead shortly after, as he jinked inside and curled his shot marginally past the post.
An unfortunate Cerv touch released Borja Sainz for a golden opportunity, although the Spaniard’s tame shot did little to trouble Florian Wiegele.
Yet, there were further scares for Plzen after Amar Memic had come close, as Wiegele’s attempted pass hit Sainz, and Jakub Kiwior’s driving run culminated in a pass that found Rodrigo Mora, although the ball bounced harmlessly behind on both occasions.
The Czech side’s lead looked more slender than ever when losing Kabongo to injury shortly after the half-hour mark due to an injury, before Matej Vydra was sent off for handling Martim Fernandes’ goalward header.
Even so, they entered the break ahead, as Samu Aghehowa hit the ensuing penalty wide.
Plzen stood firm after the restart despite their man deficit, with Karel Spacil competing especially well against Samu, and Bednarek resorted to smashing a speculative shot harmlessly off-target.
Francesco Farioli made a double substitution just 11 minutes after he had introduced Pepe at half-time, but their struggle to create clear opportunities continued as Cerv blocked the Brazilian’s attempt.
Pablo Rosario and Kiwior then sent an effort apiece wide ahead of Porto’s final alterations being made with 19 minutes remaining, while their frustrations steadily rose.
That had resulted in a member of their staff being sent off late on, but Deniz Gul got the better of Cerv in the 90th minute and smashed the ball past Wiegele to earn Porto a draw and keep them above Viktoria Plzen.
Things could have got even better, but Samu poked the ball wide shortly after as Porto’s nine-game winning run across all competitions was brought to an end, while Viktoria Plzen played out their fourth consecutive UEL draw.
Flashscore Man of the Match: Karel Spacil (Viktoria Plzen)
