Down 3-0 after the first leg at the Camp Nou, Liverpool did the unthinkable at Anfield, turning around the tie with four answered goals in one of the greatest comebacks the Champions League has ever seen.
"It doesn't feel the best at the minute but I'll get a scan tomorrow", he said following the full-time whistle at Anfield.
"Winning is hard but winning with a clean sheet, I don't know they did it".
Juergen Klopp's side will play the victor of Wednesday's other semi-final between Ajax Amsterdam and Tottenham Hotspur, with the Dutch side leading 1-0 from the first leg in London.
Liverpool will play the victor of Ajax and Tottenham in the final.
Yet, with Barca so fragile at the back, the writing was on the wall from the moment Divock Origi slotted home from close-range in the seventh minute.
Rakitic came on late on, but it made no difference and Liverpool comfortably held out in the last ten minutes to give them a famous victory on a memorable night at Anfield. Georginio Wijnaldum came on the pitch in his place.
Now Dutch midfielder Wijnaldum has joined Liverpool's European hall of fame with two quick-fire goals after coming on as a half-time replacement for the injured Andrew Robertson.
Liverpool left-back Andy Robertson was forced off at half-time during Liverpool's 4-0 win over Barcelona, casting doubt over his fitness for this weekend.
Divock Origi scores Liverpool's decisive fourth goal.
"I think it was just instinctive", Alexander-Arnold told BT Sport.
Daniel Sturridge started his second consecutive match in the Premier League as he once again stood in for Firmino.
A more natural rhythm returned to the game once the chaos of the quickfire double eased and Barcelona steadily found a foothold, Alisson having to push away a Messi punt at the near post after a clever corner routine.
But Suarez insisted Valverde, who has led Barca to two successive La Liga titles and taken them to the Copa del Rey final, should not face criticism for another European meltdown.