Wijnaldum was left on the bench in the second leg of the Champions League semi-final at Anfield, as Barcelona entered the game with a commanding 3-0 advantage after the first leg.
Divock Origi’s early goal gave Liverpool hope but the Reds still entered half-time needing two goals to level the tie.
Wijnaldum entered the game at the break and his quick-fire double in the 54th and 56th minute stunned the visitors to even the semi-final tie at 3-3.
Origi then completed his brace in the 79th minute, completing a sensational comeback and giving Liverpool a 4-0 win on the night and a 4-3 victory on aggregate.
After the game, Wijnaldum revelled in the moment and also confessed that he had a little extra motivation when he entered the game at half-time.
“What can you say, it’s unbelievable,” Wijnaldum told BT Sport. “After the game we were confident we could score four at home and win 4-0.
“The people from outside they doubted us and thought we couldn’t do it, but once again we showed that everything is possible and we won 4-0.
“Yeah, I’m really emotional because I was really angry at the manager that he put me on the bench!
“I had to do something when I came in, I had to help the team… but overall it was a team performance.
“We believed it from the start that we could win 4-0… we knew it was possible.”