Milan ended a club-record run of five successive defeats in the Champions League with a 1-1 draw against Primeira Liga leader Porto at San Siro on Thursday.
That solitary Group B point after four matches all but ends Milan's hopes of qualifying for the last 16, though, as it must win both remaining games and hope other results go its way.
Pioli's side fell behind to a Luis Diaz strike with just five minutes and two seconds on the clock – the second-fastest goal it has conceded at home in the Champions League.
Porto looked a lot sharper and should have doubled their lead when Evanilson headed against the crossbar, but Milan earned a point through Chancel Mbemba's comical own goal.
Despite remaining bottom of the group, Pioli is remaining upbeat with his side flying high in Serie A ahead of the showdown with rival and reigning champion Inter.
"The signs are positive for us, even if the team is disappointed," he told Amazon Prime. "We wanted to find our first victory in the Champions League.
"It is true that their pressure was strong in the first half. In the second half we did better. We moved better and their intensity in the pressure dropped.
"It is clear that conceding a goal like we did influenced our way of playing. I can't say much about the second half, especially in terms of our aggression.
"Porto are a strong team, who last year eliminated Juventus. The level in this competition is very high. To win in the Champions League you have to deserve it.
"The next game will be just as difficult. Inter deservedly won the championship and remain favourites to retain the title.
"We will have to play a high level match, but we have the opportunity to do well."
Milan have won just one of their past 11 Champions League games, whereas Porto have now lost just one in nine in the group stage.
The Portuguese side had a three-day gap between their 4-1 win against Boavista and the game at San Siro, compared to a couple of days off for Milan following their win at Roma.
That was also the case prior to last month's reverse fixture, which Porto won 1-0.
"They played a day before us twice in a row," Pioli said. "If you have seven or eight days to recover it doesn't make a difference.
"But if you have three instead of four in a period where you play seven times in 21 days, it can make a difference."
Olivier Giroud was selected ahead of Zlatan Ibrahimovic up top for Milan but could not find a way through as his scoreless run in the competition stretched to 326 minutes.
At 35 years, Giroud was the oldest member of Milan's line-up and feels a lack of experience has perhaps cost his side in Europe this term.
"We're a young team but I don't want to make excuses," he told Canal+. "We also needed a little more luck. We have played some good matches in the group.
"It's tough against teams who are used to Champions League football like Porto or Atletico. Experience is important.
"Now we've got the derby with Inter and we will look to come back with the same energy and desire for that game."