The Zenit boss was full of praise for the Brazil international who crossed for Aleksandr Kerzhakov to net the only goal of the game in the Russians’ 1-0 victory at the Dragao
The Brazil international, who spent four years at the Dragao, was in fine form and it was his cross that provided Aleksandr Kerzhakov with the opportunity to head in the only goal of the game with just four minutes remaining.
Spalletti was delighted with the 27-year-old’s showing on what was an emotional return for the €40 million (£33.95m) man.
"Hulk was the player that gave them the most problems," Spalletti told reporters.
"He was everywhere, dribbling from the right, providing Kerzhakov with the goal - he was crucial in our win."
The Italian also gave his backing to referee Paolo Tagliavento, insisting the official was correct to hand Hector Herrera a sixth-minute red card.
The Mexican was given his marching orders after receiving two yellow cards in the space of a minute.
His first was given for a tackle from behind on Hulk which was immediately followed by a foolish second for encroachment on the resulting free kick.
"I think it was a correct decision by the referee," added Spalletti.
"I would be surprised if he didn’t see the second yellow."
The win lifts Zenit to second in the group, while Porto drop to third - one point behind the Russian side.