The Barcelona star has now scored four goals in Brazil ahead of the Albiceleste's last-16 clash with Switzerland on Tuesday, one short of Diego Maradona's tally in 1986, and is now just 14 short of Gabriel Batistuta's all-time national record of 56.
And Romero is hopeful that Messi can continue his group-stage form in the knockout rounds after scoring winning goals against both Bosnia-Herzegovina and Iran so far.
"As I said last time, Leo has returned to rub the lamp," the 27-year-old was quoted by AS.
"He always does something different - we are lucky to have him. It's hard to find words to define Leo's awesomeness. He makes us all very happy to have him at this level and as a team he will help you to keep playing this way."
Messi scored all but two of Argentina's six goals as they topped Group F and defender Federico Fernandez echoed Romero's words on the importance he has in Alejandro Sabella's side, particularly now Sergio Aguero has suffered a muscle tear.
"Messi is an absolute star," the Napoli centre-back said.
"He's just a different player. I enjoy seeing him play. Thank goodness I don't have to mark him."