The Madrid star was angered by Spanish radio and television presenter Juanma Castano describing the European champions' controversial elimination of Juve on Wednesday as "a scandal" and "a robbery", following a late penalty given in Lucas Vazquez's favour at the Santiago Bernabeu.
The kick was converted by Cristiano Ronaldo past Wojcech Sczeszny in the Juve net, as Gianluigi Buffon was red-carded for his protests to referee Michael Oliver after the decision was made.
That strike meant Madrid advanced 4-3 on aggregate, cutting short a stirring comeback by the Serie A holders at the Bernabeu.
Una profesión, dos varas de medir , vergonzoso🤮 pic.twitter.com/HQnj4V2MoY— ISCO ALARCON (@isco_alarcon) 13 de abril de 2018
The assessment particularly frustrated Isco because Barcelona's stunning comeback against Paris Saint-Germain in last season's Champions League - complete with its own contentious decisions - was "historic" in the eyes of the same reporter.
Spain international Isco vented on Twitter, posting alongside footage of the analysis: "One profession, two measuring sticks - shameful."
Madrid have drawn Bayern Munich in the semi-finals as they look to win the Champions League for a third consecutive season.