Porto will be optimistic with their chances of progressing to the last 16 phase of the tournament after reaching the same stage last season.
Schalke, meanwhile, will relish being back in the Champions League after missing out on a place in it last year.
Goal will take a look at the rundown of the Group D fixtures ahead of the group phase start, as well as what to expect from each team and more.
Champions League 2018-19 - Group D Fixtures
Porto were subjected to a debilitating 5-0 loss to Liverpool on home ground in the first leg of the Champions League last 16 in 2017-18, with Sadio Mane netting a hat-trick.
The Portuguese side were unable to quell a rampant Liverpool side that ran riot on the night, but managed to hold the Reds to a 0-0 stalemate in the reverse fixture (though were already eliminated by that point).
Schalke finished second in the Bundesliga to earn re-entry to Europe's elite competition following their disappointing 10th-placed finish in the previous season, and are fortunate not to have drawn the bigger guns – faced with the likes of Lokomotiv Moscow and Galatasaray.
The Turkish champions also missed out on Champions League action last year after losing their qualification rounds, though return this year.
Champions League 2018-19 - Group D Table Standings
Champions League 2018-19 - Group D Squads
Lokomotiv Moscow: Guilherme, Nikita Medvedev, Anton Kochenkov; Bryan Oladapo Idowu, Benedikt Howedes, Vedran Corluka, Taras Mikhalik, Boris Rotenberg, Maciej Rybus, Solomon Kverkvelia, Mikhail Lysov; Manuel Fernandes, Dmitri Barinov, Grzegorz Kyrchowiak, Jefferson Farfan, Anton Miranchuk, Aleksandr Kolomeytsev, Vladislav Ignatyev, Dmitri Tarasov, Igor Denisov, Alexander Vulfov, Aleksei Miranchuk, Roman Tugarev, Daniil Kulikov, Nikita Dorofeev, Dmitrii Rybchinskii, Ivan Galanin; Fedor Smolov, Edderzito Antonio Eder, Rifat Zhemaletdinov
Porto: Iker Casillas, Vanailson Luciano de Souza Alves, Diogo Costa; Maxi Pereira, Eder Gabriel Militao, Diogo Leite, Alex Telles, Jorge, Felipe, Chidozie Awaziem, Bruno Costa, Yacine Brahimi, Olivier Torres, Hector Herrera, Danilo, Riechedly Bazoer, Otavio, Sergio Oliveira; Hernani, Vincent Oaboubakar, Moussa Marega, Jesus Corona, Adrian Lopez, Andre Flipe Ferreira Coelho Perieira
Schalke: Ralf Fahrmann, Yannic Lenze, Alexander Nubel; Hamza Mendyl, Matija Nastasic, Sebastian Rudy, Abdul Baba Rahman, Salif Sane, Ronaldo Aparecido Naldo, Niklas Wiemann; Weston McKennie, Omar Mascarell, Suat Serdar, Nabil Bentaleb, Yevhen Konoplyanka, Benjamin Stambouli, Daniel Caligiuri, Amine Harit, Jannie Kubler, Alessandro Schopf, Benjamin Goller; Mark Uth, Franco Di Santo, Ahmed Kutucu, Guido Burgstaller, Steven Skrybski, Cedric Teuchert, Breel Embolo
Galatasaray: Fernando Muslera, Ismail Cipe; Mariano Ferreira, Maicon, Serdar Aziz, Ahmet Calik, Martin Linnes, Omer Bayram, Yuto Nagatomo, Selcuk Inan, Younes Belhanda, Ryan Donk, Badou Ndiyae, Emre Akbaba, Fernando, Sofiane Feghouli; Garry Rodrigus, Eren Derdiyok, Sinan Gumus, Henry Onyekuru, Mugdat Celik
TV Channel, Live Stream & How To Watch
In the United States (US), Champions League games will be shown on Univision Deportes and streamed online through B/R Live .
|US TV channel||Online stream|
|Univision Deportes||B/R Live|
In the United Kingdom (UK), the game can be watched live on BT Sport and streamed through the BT Sport app .
|UK TV channel||Online stream|
|BT Sport||BT Sport app|