The Spaniards trail 1-0 in the tie ahead of Thursday's game and Emery now has fresh material to use for inspiring his players, after some impressive comeback efforts in the Champions League this week.
"We'll have to take care that they don't score against us and that we're closer to scoring goals ourselves, but we have to be prepared for a situation that they do score, whether it's early or late in the game," said the former Valencia boss.
"We have to be patient. We have seen that there were two good examples with Borussia Dortmund and Chelsea, we should have a similar response in our game.
"We have to make it a long game for our opponents, because that will give us more options as the game progresses."
Dortmund fell one goal short of forcing extra-time in their tie with Real Madrid, despite trailing 3-0 after the first leg, while Chelsea arrested a two-goal deficit to progress to the last four at the expense of Paris Saint-Germain.
Sevilla will benefit from the absence of Jackson Martinez and Fernando for the visitors, although Emery believes Porto's strength in depth means they are capable of covering the hole left by the pair.
He continued: "They are not going to have those two available, but they'll have another two playing and a strong XI.
"If you're playing for Porto, it is because you are a good enough footballer. I'm not evaluating them based on any of their absences, but rather that they'll have two different players involved."
Emery is so focused on the European fixture that he insists Sevilla's derby with Real Betis in the league on Sunday - which could see them push their rivals to the brink of relegation - is not on his radar.
"What derby? All our enthusiasm and focus is on the Porto game," Emery said.
"We have to make a big effort together, to enjoy this moment and make the most of it. That's the enthusiasm we have to convey, to create a positive atmosphere, that we feel the support of our 12th man in the crowd."