The Portuguese starlet came on with the score level at 2-2 and impressed during his few minutes on the pitch, as the Reds secured a vital last-gasp victory thanks to a Steven Gerrard penalty in the 90th minute.
And Liverpool boss Brendan Rodgers was delighted with the 21-year-old's contribution, praising his dedication to his team-mates, as well as his defensive efforts.
"Tonight you saw the real development of the team in terms of character yet again," Rodgers told reporters after the game.
"You saw young players in pressure situations stay calm and stay focused.
"We introduced another young player in Joao Teixeira, who has done great in our reserve team.
"Not only did he show that he could come in and play with some of our top players, he's also shown he can fight for the team. He made a great block at the end and it was equally important for us."
Rodgers also spoke about another second-half substitute, who came on 10 minutes after Teixeira - in injury time - but was equally important in securing the points for Liverpool.
That substitute was Daniel Agger, finally back from injury, with the Reds boss explaining the thinking behind the last-minute switch.
"Daniel Agger had been out for a while. I said to him that, if the penalty went in, he was going straight on, so to get ready," Rodgers said.
"I had an idea that with the big guy coming up front, it would become a war for the last five minutes.
"As soon as it went in, Daniel was coming on and he made three great headers in the end to prevent us from conceding."
image: © nathan17