Two Champions League nights shaped by defences that have recently lost key players. In Istanbul, Stuttgart's tight European numbers were built by a back line that is not available, and both attacks have recently found defences like the ones they face here. At Camp Nou, Barcelona's attack is intact but their defence is patched, against a Villa counter that scores against top sides.
Galatasaray against Stuttgart: Stuttgart's low expected goals against in this competition came with Stiller and Vagnoman playing, and both are out. Without them, Stuttgart gave up 24 shots at Leverkusen and plenty of chances against Gladbach. Galatasaray's front line is fit and sharp, with Osimhen scoring in each of their last three wins. Their own defence leaked heavily against Lille and Barcelona, and all three of their European games this season had at least four goals.
This works however possession falls. If Galatasaray push on with the crowd, Stuttgart can hit them directly, as they did at Leverkusen on little of the ball. If Stuttgart hold the ball, Galatasaray's runners get in behind high full-backs. Whoever scores first, the second half should open up, with Sané and Gündoğan to come off Galatasaray's bench. I expect goals at both ends in Istanbul.
Barcelona against Aston Villa: Barcelona's big wins came against weak opponents, like the rout of Alavés, who had under a quarter of the ball. Against PSG and Real Madrid they scored one and two and lost both. Since then the defence has got thinner: Koundé, Eric García, Christensen and Espart are all out, and De Jong has been playing at centre-back.
Villa have scored in nine of their last ten and led Manchester City, Tottenham and Newcastle with this away plan: a compact block with Kamara screening, then quick breaks to Jackson through Buendía and Manzambi. Barcelona will have the ball and should score, but a heavy margin needs Villa's block to collapse, and it hasn't done that against good sides. I'm siding with Villa to keep this within reach.