Milan Badelj had opened the scoring in Bergamo, but Andrea Petagna's header equalised on the stroke of half-time.
“I am satisfied with the performance, as we never stopped attacking, even in the most difficult moments," Pioli told Sky Sport Italia.
“There are regrets, because we had other chances to score, but weren't sharp enough in our finishing. Atalanta changed their shape in the second half and took over more of the pitch.
“We must improve our choices in attack if we are to start getting wins rather than draws, which would better reflect our performances."