Liverpool put themselves well into the ascendency of their Champions League tie with Porto after their 2-0 win at Anfield last week.
The Reds eased to victory, with their goals coming from Naby Keita and Sadio Mane.
But the game was not as cut and dry as some might think. Porto had a couple of very good chances of their own, and on another day, the score could have been a lot different.
Porto are a tough side, and they are hard to beat for any team. If the Portuguese outfit grab an early goal, it could potentially be very edgy for Liverpool.
The Premier League leaders must keep in mind that if they score one goal, Porto will have to score four, making an already uphill task near on impossible.
But here we will take a look at some of the key battles going into this game, which will decide who makes it into the Champions League semi-finals.
Mohamed Salah v Alex Telles
Mohamed Salah has been showing signs of his very best form in recent weeks, and he caused lots of problems for Chelsea’s Emerson at the weekend.
Alex Telles has proven to be a very talented full-back, but if Salah is firing on all cylinders, he is going to be tough to stop for any defender in world football.
Jordan Henderson v Hector Herrera
Hector Herrera has been an integral member of the Porto setup for six years now, but he missed the first leg through suspension.
Jordan Henderson has been playing really well of late, and it will be a good indicator of where his game is at when he comes up against Herrera on Wednesday.
Both are tough fighters in the midfield area, and the winner of this battle could prove influential.
Alisson v Moussa Marega
Moussa Marega is Porto’s second top goalscorer in all competitions this season, but two massive chances fell to him in the first-leg that he squandered.
Marega scored in the league at the weekend so he should be full of confidence going into this one, and he will have to perform if Porto have a chance of advancing.
Roberto Firmino v Felipe
The Brazilian compatriots will be very familiar with one another following their encounters over the past two seasons.
Firmino is just finding form at the right time with a few games to go, as in his last five games, he has three goals and two assists.
It is sometimes too easy to focus just on Salah’s importance for Liverpool, but to have a chance, Porto will have to keep his strike partner Firmino quiet as well.