Gerrard feels all eyes would be on the pair if he selects the Colombian up front but he believes his top goalscorer would relish the challenge of facing 36-year-old defender Pepe, who has been a European champion three times with Real and once with his country.

Morelos has scored 15 goals already this term, nine of them in Europe.

"Listen, if Alfredo is selected to play it will be a fascinating battle," Gerrard said. "Pepe has been a world-class player throughout his career, a very decorated individual who I have a lot of respect and admiration for.

"But Alfredo is in a good place, he is playing well, he is in good form and I'm sure he will be itching to start. I'm sure he will be looking forward to testing himself against the best.

"There will be a lot of really intriguing key battles across the pitch but I'm sure all eyes will be on that one."

Gerrard believes facing a team which reached the last eight of the Champions League last season in the 50,000-seat Estadio do Dragao can inspire his players.

"From my point of view it has to," he said. "I don't think this is an arena or fixture where you can come and perform below par. If we have got any ambition to take anything away from this, whether it's a win or a point, we have to max out, that's in and out of possession.

"We have to find a performance that's close to our best to take something, we are well aware of that.

"But I have belief in the players that we can find that because coming to a place like this, an arena that has the wow factor, a pitch that's perfect, against an opposition that all the players will have huge respect for, more often than not that's when you can find your performance.

"And that's why I'm really looking forward to this fixture because I think we can really put in a proud performance."

All four teams in the group have three points after each won their first home game, and Rangers blew the chance to go top after conceding a soft stoppage-time goal against Young Boys in Switzerland. Gerrard believes they have learnt from that experience.

"It's important we have that concentration and focus from start to finish because if anyone loses it, at this level you get punished," he said. "Top players can always punish you.

"It's something we speak about on a regular basis and the players hopefully have learnt from Young Boys because the challenge is difficult enough without individual mistakes. But I'm sure we have.

"To be fair to the players, every challenge that has been put in front of the players, certainly from a European point of view, they have done ever so well considering the time we have been together.

"No one gave us a chance last year when we went to places like Villarreal but we found a performance and were unlucky not to win that match.

"That's the type of performance we are going to need to have because I don't think many across the board are going to give us a chance against opposition like Porto.

"Hopefully that will galvanise us and we'll all pull together and be in the right place to take something."