The Reds were switched on from start to finish with Jeronimo Neumann's brace – including a stunning candidate for goal of the year – complemented by goals to Sergio Cirio, Fabio Ferreira and Awer Mabil, as the stunned visitors left the country with their tail firmly entrenched between their legs.
The evening got uglier and uglier for the Phoenix throughout, a stark contrast to United's celebrations which hit fever-pitched towards the end.
Gombau wants his side to maintain their hardened, focused edge, knowing full well a finals spot is still not guaranteed such is the congested nature of the competition table.
"These six games need to be like six finals," Gombau said.
"In football if you lose concentration and focus, you can lose (matches).
"We need to work very hard every single game to be in the six.
"I don't want them to relax."
Responding in style to last week's loss against Melbourne Victory at AAMI Park, Gombau revealed his pre-match message wasn't about turning the result around.
It was around understanding the side is playing extremely well, results aside.
"I said to the players before the start, the Sydney game was very good, the Central Coast game was very good, the Melbourne game was very good… don't change," Gombau said.
"Play the same, don't think win-lose.
"(I want them to) just think we are playing well. I am so happy.
"Even last week when we lost in Melbourne, we played very well but we had these mistakes that punished us a lot."
Despite the ease of their victory, the Reds had to overcome a few hurdles from within.
They were without centre-back Jon McKain (suspended) and playmaker Marcelo Carrusca (adductor strain).
"We didn't have McKain and 'Celo (Carrusca), who are normally in our first 11," Gombau said.
"The players that played their positions did very well."
United then lost striker Bruce Djite (groin) and last week's hat-trick hero Cirio (concussion) during the match.
Gombau substituted Djite off as a precaution in the 53rd minute but held more serious concerns for Cirio, hammered in a 50-50 clash with Manny Muscat which left the Spanish right winger dazed and literally confused.
"Djite at half-time told me he is feeling bad in his (groin) muscle," Gombau said.
"We are winning 2-0 and at that moment we didn't want to take the risk because he is very important.
"Cirio had concussion… he said that he can play but then in one moment he asked 'have I scored in this game?'
"We decided to change because it was risky. The doctor took him and they will try to check exactly what is his situation.
"He's not in the changing room, he's left to go to the hospital.
"I hope and wish everything is OK."
