Barca signed the Chile international from Italy's Udinese last year for a deal including variables that could rise to some 37 million euros, but he has yet to really make his mark at the Nou Camp.
"We haven't seen the best of Alexis yet," the 23-year-old told a news conference.
"I am finding some form and as each game goes by I am improving a little more."
Alexis was Barca's second-highest scorer behind Lionel Messi in La Liga last season with 11 goals, but suffered a string of niggly injuries in his first campaign.
Under new coach Tito Vilanova this year, however, he has yet to score and he is struggling to make the starting 11 with competition from players such as Pedro, David Villa and youngster Cristian Tello.
"I need to get into the games more and take people on in one-on-one situations," he said.
"I know I can win a place. Step by step I am making my name here because I am Alexis. I would rate myself with a five (out of 10)."
Barcelona top La Liga with five wins from five games and, after visiting Sevilla on Saturday, return to Champions League action away to Benfica next Tuesday.
They top Group G after last week's 3-2 home win over Spartak Moscow.
- La Liga
- Lionel Messi