Jesus opened the scoring in the 19th minute from close range before setting up Roberto Firmino for a routine finish in the second half.
The Manchester City striker ended a four-game run without an international goal on one of the biggest stages and in front of his home fans.
"I'm speechless. I consider every match to be important, even the ones I don't perform well, because I take lessons from them," Jesus said post-match.
"Tonight I was decided to score, I was very confident from the kick-off.
"I missed a chance, then I managed to score. Firmino was able to spot me well, it gave me confidence."
Jesus will be desperate to get on the score sheet once again in that match and despite his recent barren run, has proven a reliable goal scorer for his nation.
His effort against Argentina was his 17th goal overall for Brazil with the former Palmeiras striker netting twice on his senior debut in 2016 against Ecuador.
Though Brazil have struggled at times on home soil at this Copa America, Jesus believes his side have turned a corner and are well poised for a strong showing in the final.
"I'm very happy not only for the goal, but for how the team performed," he said.
"Last week I've said they would struggle to break our defence. We worked hard and battled hard tonight. Unfortunately we couldn't score against Paraguay but we grabbed the goals tonight.
"Everyone should be pleased for the match they played, for the effort. This is Brazil! We have to play every match as we've been playing, with the same spirit, that way we will achieve our goals."
Brazil last won the Copa America in 2007 and were knocked out in the group stages in 2016.