Key events
Some pre-match reading courtesy of Michael Butler.
It looks like Gray will be at left-back for Spurs as Postecoglou keep testing to see how many different positions the central midfielder can play.
Starting lineups
Galatasaray (4-4-2): Muslera, Khan Ayhan, Sanchez, Bardakci, Yilmaz; Yunus Akgun, Torreira, Sara, Mertens; Osimhen, Icardi
Subs: Batuhan Sen, Guvenc, Demirbay, Berkan Kutlu, Ziyech, Jelert, Nelsson, Demir, Batshuayi, Ali Yesilyurt, Efe Akman, Metehan Baltaci
Tottenham (4-3-3): Forster; Pedro Porro, Dragusin, Davies, Gray; Bergvall, Bissouma, Maddison; Johnson, Lankshear, Son
Subs: Vicario, Austin, Udogie, Dorrington, Bentancur, Sarr, Kulusevski, Cassanova, Olusesi, Williams-Barnett, Solanke
Preamble
It is three wins in three for Ange Postecoglou in Europe but this trip to Istanbul is the trickiest of the tests thus far. Galatasaray have seven points in the competition and are undefeated this season, winning nine out 10 matches in the Turkish Super Lig. They possess a glorious array of former Premier League and Serie A talent, mixed with some domestic promise and they will be eager to make a mark in Europe.
Spurs have some injury issues to consider after Cristian Romero and Richarlison were injured in the recent victory over Aston Villa. They are already without Micky van de Ven, so the defence will be tested against Mauro Icardi and Victor Osimhen.
It will be a lively night inside RAMS Park.
Kick-off: 5.45pm GMT.
