Domestically, Porto have been relentless. They have won all ten of their Primeira Liga matches, including a 3-1 home win over Benfica, and have conceded only four league goals along the way. Saturday's 4-0 win over Estoril was their third straight victory in all competitions. Europe has been a different story: a 2-0 home defeat to Manchester City, a 3-2 loss at Real Betis and a 1-0 home defeat to PSV leave them with two goals scored and six conceded after three matchdays. Farioli is without Chris Smalling, who has a knee ligament injury, as well as William Gomes and Vasco Sousa, while Oskar Pietuszewski is a doubt after returning to training. Pepê remains central to the attack.
Napoli arrive in poor shape. Allegri's side lost 1-0 at home to Arsenal and 3-1 at Villarreal before beating Bodø/Glimt 4-3, and in Serie A they have 14 points from ten games after Sunday's 2-0 defeat at Juventus. The absence list is long: Italian reports name ten unavailable players, including Stanislav Lobotka, Giovanni Di Lorenzo, Alessandro Buongiorno, David Neres and Leonardo Spinazzola. Kevin De Bruyne travelled with an ankle problem and is a doubt, while Rasmus Højlund has shaken off a fever and is expected to lead the line. With only three senior centre-backs available, Allegri is expected to switch to a 3-5-2, with Billy Gilmour, Frank Anguissa and Scott McTominay in midfield.
The clubs' last competitive meetings came in the 2013/14 Europa League round of 16, when Porto won 1-0 at home and drew 2-2 in Naples to go through. That tells us little about Wednesday. More relevant is how the sides match up now. Porto press high and have kept things tight at the Dragão, with clean sheets in their last two home wins against Académico de Viseu (1-0) and Estoril (4-0). Napoli's matches have been far more open, with a 3-3 draw against Roma and the 4-3 against Bodø/Glimt, but a depleted midfield without Lobotka and possibly De Bruyne gives Allegri every reason to set up cautiously. "In the Champions League, our destiny is in our hands," he said, while stressing that Serie A remains the priority.
The main risk is obvious. Napoli's games have often been chaotic, and if Porto score early, the visitors will have to open up, which could turn this into a much more stretched contest. Porto's defence has also looked more vulnerable in Europe than at home, with six goals conceded in three matches, and a single set piece or error against a reshuffled back three can change the picture quickly. We still prefer the goals market to backing a winner. Porto need three points, but a 1-0 or 2-0 is a realistic route there, and a cautious Napoli without key creators makes a low-event game more likely than the price suggests. Under 3.5 goals gives more margin, but at a price with far less value.
Under 2.5 goals is available at 2.20 with Sky Bet via OddsCapo, which corresponds to an implied probability of 45.5 per cent. We put the chance of two goals or fewer at around 49 per cent, based on Porto's domestic defensive record, Napoli's injury list and the likelihood of a tactical, cagey evening in Porto. The edge is modest rather than large, but it is there, and that's why we're backing Under 2.5 goals at the Dragão.
Betting tip: Under 2.5 goals @ 2.20 (Sky Bet)
Odds were taken from OddsCapo on Wednesday and may have changed. Always check the price with the bookmaker before you bet.
18+ | Gamble responsibly | Stodlinjen.se
Photo: Estádio do Dragão, Porto by Edgar Jiménez, CC BY-SA 2.0, via Wikimedia Commons.
