© Copyright khedmeh Wall
It was a hugely important goal for Ralf Rangnick's side, who had been on the back foot for the vast majority of the tie.
Joao Felix gave Diego Simeone's side the lead with a brilliant diving header from Renan Lodi's near-post cross.
Elanga came off the bench for Marcus Rashford in the 75th minute and made an impact five minutes later by running onto Bruno Fernandes' through-ball to beat Jan Oblak.
Savage was calling the goal live while on co-commentary duty for BT Sport and was full of praise for the 19-year-old striker.
Elanga has won the trust of interim manager Rangnick, who has now used him in 11 successive games, either as a starter or off the substitutes' bench.
The goal in Madrid was his third in 14 appearances this season and his second in successive games, following his strike in the 4-2 win over Leeds.
Former United midfielder Scholes praised Rangnick's decision to bring Elanga on, but thought his goal owed a lot to good fortune.
Elanga was delighted with his goal, which came from United's first shot on target and, he believes, his first touch.