Portugal needed at least a draw against Ireland to get the 1st place over Serbia because of the goal difference and they got it, the game ended 0:0 but to be fair Portugal played one of their worst games but usually Portugal has struggles against teams like Ireland because of their physical play but they got what they need it, now they will try to defend the 1st place against Serbia today at home. Portugal is one of the strongest teams of the World, if we look at their players they are not many teams better than Portugal and at home they usually are a really strong team and in this group they have won all their three home games with 8:1 in goals. One bad news for Portugal in the game against Ireland was that Pepe got a red card and will miss this game but Fonte is a nice player and I don't think that will be an issue for Portugal, even Pepe is clearly the better player but overall I give the edge to Portugal in every sector against Serbia.

Serbia have the same points than Portugal and will fight for the direct access to the World Cup and for that they need to beat Portugal on the road because a draw isn't enough and I think that's a big task to ask them, even Serbia hasn't lost any road game so far, 2 wins and 1 draw they performances were always bad and their wins were minimal against teams why weaker than Portugal and also we saw in the 1st game between them that Portugal attack gave them huge problems and it will be hard for Serbia's defensive line to be able to stop Portugal attack from scoring here in my opinion, especially facing them on the road.

The 1st game between both teams ended 2:2, Portugal was 2:0 up and relaxed and Serbia took advantage of that and managed to score two goals, but also we can't forget that if that game had VAR, Portugal would have won the game 3:2 because Ronaldo scored a legit goal in the end of the game where the ball was clearly behind the line but the side referee missed that and there was no VAR. For Portugal a draw is enough but Portugal at home can't focus on a draw, that's also not their way and especially playing in the Stadium of the Light Portugal has a great atmosphere and usually have tremendous results, I expect Portugal to win this game, they are for me the much better team here and Serbia on the road hasn't been impressive. I expect Portugal to score multiple times in this game and I don't see Serbia being able to that, I also like the fact that for Serbia only the win matters, so they will need to risk more in this game what is also a think that will favour Portugal's strenght. 

Good Luck