Rennes against Olympiacos is a home volume side meeting the tightest away block in the Europa League, and Rennes' own back line is leaking badly right now. In Porto against Napoli, the absences pile up in Napoli's defence rather than their attack. Porto have to win, so they will attack, and they have conceded in every Champions League game. Both matches point the same way: the side the market treats as weaker keeps a real route of its own.
Rennes win games through volume. They average around 18 shots, the wing-backs push high and Szymanski and Dia arrive late in the box. At home they have been very strong. The problem is at the back: eleven goals conceded in their last four, penalties given away in three of them, and more than three expected goals allowed at both Nice and Paris FC.
Olympiacos do the opposite. Their Europa League opponents have managed between roughly half an expected goal and just under one per game, and that includes the away trip to Marseille, where they had less of the ball, scored before the break and saw the game out. El Kaabi's injury looks like big news, but he was already missing for that whole run. Gonzalez, Yaremchuk and Hezze scored those goals, so the attack that plays here is the one that won three straight.
Lepaul's absence takes away Rennes' top scorer and penalty taker. Their creators are still there, but against a compact mid-block with Hezze and Freuler screening, I expect crosses and second balls more than clear chances. Rongier and Ait Boudlal are both carrying knocks. Olympiacos have the transition, set pieces and a bench (Yaremchuk, Fortounis, Bailey) to find at least one goal. That's why I'm siding with Olympiacos to come away unbeaten.
In Porto, Napoli have lost three of the four defenders who started their last match. Di Lorenzo and Olivera are out and Marianucci was sent off, so Allegri looks set for a makeshift back three with Politano and Lang, forwards by trade, playing wing-back. That puts them straight up against Porto's full-back overlaps and crossing game.
Napoli's attack is a different story. Neres was coming off the bench, and Hojlund, Politano, Lang and McTominay are all available. Porto have conceded in all three Champions League games and allowed well over one and a half expected goals each time. With no points on the board, Farioli has said he won't change his approach, so his full-backs will push on and leave space behind for Hojlund. Marin and Rrahmani have also both scored with headers from set pieces recently. I expect Porto to break through a patched-up line and Napoli to answer in transition or from a dead ball. That's why I'm siding with goals at both ends in Porto.
