The Argentine made a €39.2 million move to the Ligue 1 side during the summer and has begun his career in France with a bang, scoring five goals already this season.
Chelsea were also rumoured to be in contention to sign Pastore instead of continuing their pursuit of Luka Modric, which eventually ended in them signing Raul Meireles from Liverpool, and Arsenal boss Wenger says he likes the like of the 22-year-old.
"I like this player," he said. "He has talent, a form of natural elegance, and a mental elegance too. I like him, I like him."
Arsenal were in the market for a playmaker this summer, with Eden Hazard and Marvin Martin both linked with a move to north London.
The sale of Cesc Fabregas and Samir Nasri eventually sparked Arsenal into action in the transfer market, with Mikel Arteta and Yossi Benayoun joining the club in the twilight of the transfer window.
While Chelsea's pursuit of both Pastore and Modric both failed, they were able to recruit Meireles and Juan Mata, who has been a revelation since joining the club.
Mata helped create two Chelsea goals against Everton on Saturday, assisting in Ashley Cole setting up Daniel Sturridge, before finding Ramires in the second half as the Blues closed the gap at the top of the Barclays Premier League.