The Spanish right-back opened the scoring in the 39th minute with a header, but Kaoru Mitoma levelled with a wonder goal in first-half stoppage time. Xavi Simons put Tottenham back in front with a stunning strike in the 77th minute, only for Georginio Rutter to equalise deep into added time and deny De Zerbi's side their first league win since December.
"I think after the game, we don't have time for disappointment," Porro told BBC Sport. "For me and my team-mates, the best thing is to keep pushing, keep going."
"I think the team today was very good. I think the first half was very good for us. The team pressed very well. The most important thing is to remain positive."
Head coach Roberto De Zerbi, who was managing his first home game since taking charge, praised his side's "character and spirit" but acknowledged they are "suffering too much."
It was De Zerbi's first match as Tottenham manager at the Tottenham Hotspur Stadium after losing his opening game 1-0 at Sunderland.
Spurs remain 18th in the Premier League on 31 points from 33 games, two points from safety with five fixtures remaining. West Ham United and Nottingham Forest, both above them in the table, play across the next two days.