Simeone said he was delighted with Alvarez's maturity and humility as well as his determination to work hard and stay focused despite a slow start in his debut season in the Spanish capital.
The coach said the Argentine was everything they needed him to be when Atletico signed him in the close season in a deal worth some 75 million euros ($78.44 million) plus 20 million in potential add-ons from Manchester City.
"When he still couldn't reflect with facts what we were looking for when we signed him, I said that I was sure he had Atleti's DNA," Simeone told a press conference.
"That's why we were so excited then and we are now. Especially because of the way he does things. He won everything by the age of 25 - the World Cup with Argentina, the Champions League and the Premier League with Manchester City, and he continues in the vein of that humility that makes him different from everyone else."
With the win, Atletico took top spot temporarily in LaLiga on 53 points, before Barcelona moved back to the summit with a 2-0 win over Las Palmas in the evening.