Eusebio Di Francesco felt Roma did not get what they deserved after Porto grabbed a late away goal in the first leg of their last-16 Champions League tie.
Nicolo Zaniolo scored twice in a six-minute spell in the second half to put the hosts in control at the Stadio Olimpico, only for Porto to cut the deficit in half in fortunate circumstances.
Tiquinho Soares' ambitious shot from distance inadvertently set up substitute Adrian Lopez to score as the game finished 2-1 to Roma, leaving Di Francesco with mixed feelings.
The Roma boss was quick to praise his players for their "high-level" display after a mixed run of results in recent weeks, meaning they hold a slender lead heading into the return fixture on March 6.
"It's too bad about the result. I have praised the guys for the attitude and the attention shown in both phases of the game," Di Francesco told Sky Sport Italia.
"There was a lot of solidity, we knew what we wanted to do and we hit at the right time, creating many situations to hurt our opponents while giving away very little.
"It is a pity about the goal, because it is not really our mistake. The boys have worked well in every sense - there have been errors, but they can happen.
"We deserved to win by two goals, that is the regret. But I hold on to this high-level performance."
Teenager Zaniolo opened the scoring by angling a right-footed shot beyond Iker Casillas, while he was on hand to make it 2-0 by converting the rebound after Edin Dzeko's drive had struck the post.
"I think the lad must be allowed to grow," Di Francesco said when asked about Roma's two-goal hero.
"I told him to keep playing with his head, as a goal can take you out of the game and create enthusiasm that is distracting, but he was not only focused, he scored a second.
"We have a player with immense talent and we are very glad to have him here."
In contrast to his opposite number, Porto boss Sergio Conceicao felt his side deserved to be on level terms heading back to Lisbon.
"In the second half, we had a chance from Danilo [Pereira] and in our best moment we ended up conceding," the former Lazio player told the media.
"Their second was a bit bizarre, but we didn't stop looking for the goal. The players reacted like I expected to, with character, personality and knowing that there are another 90 minutes to go.
"Our goal leaves it all open for second leg, but a draw would have been a fair result."
