Arsenal host the holders in the first leg of the Champions League round of 16 and it will be the first time Chile star Sanchez has faced his old club since moving to north London in July 2014.
The 27-year-old won La Liga and the Copa del Rey during three seasons with Barcelona but, having already scored 35 goals and lifted the FA Cup in Arsenal colours, feels he made the switch at the ideal time.
"I never regret my decisions," Sanchez told the Sunday Mirror. "It wasn't easy to leave Barcelona.
"I fulfilled a dream when I moved there - to play in Spain and for the champions - but very few players stay in the same club all their life. To leave is normal.
"I wanted a new project, a new experience. And with so many attacking players at Barca it was a good choice to go.
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"I think it was a good choice to go to Arsenal, the best choice. It has been a positive move and I love it at Arsenal."
Sanchez, who moved to Barcelona from Udinese in 2011, does not know if he will celebrate or not should he find the back of the net against his former team.
"I'm a professional so any match against Barcelona in the Champions League is special to me," he said.
"I can't say what my reaction will be if I score. That depends on the moment."