Team news - Messi starts
Argentina v Saudi Arabia (10:00 GMT)
Kick off is approaching so here's a reminder of the team news.
Lionel Messi had spent a period training away from the Argentina squad in the build-up to this tournament, but the forward starts and captains the side in what may be the opener to his World Cup swansong. He is one of what is a fearsome front three, along with Inter Milan's Lautaro Martinez and Juventus' Angel di Maria.
Manchester United defender Lisandro Martinez misses out through injury and so Tottenham's Cristian Romero partners Nicolas Otamendi at the back.
Aston Villa keeper Emi Martinez starts in goal.
Argentina: Damian Martinez, Tagliafico, Romero, Otamendi, Molina, Paredes, De Paul, Messi, Di Maria, Gomez, Lautaro Martinez.
Subs: Armani, Foyth, Montiel, Pezzella, Acuna, Alvarez, Palacios, Correa, Almada, Rodriguez, Mac Allister, Dybala, Fernandez, Lisandro Martinez, Rulli.
Salem Al-Dawsari is the man to watch for Saudi Arabia. He starts on the left wing, with Saleh Al-Shehri - top scorer in the third round of AFC qualifying with four goals - is on the opposite side.
Midfielder Riyadh Sharahili misses out through injury but defender Hassan Tambakti starts having overcoming a fitness issue of his own.
Saudi Arabia: Al-Owais, Al-Bulayhi, Abdulhamid, Al-Shahrani, Tambakti, Al-Malki, Salem Al-Dawsari, Al-Shehri, Kanno, Al-Faraj, Al-Buraikan.
Subs: Al-Rubaie, Al-Ghanam, Madu, Al-Amri, Al-Burayk, Otayf, Al-Hassan, Al-Naji, Al-Abed, Bahbri, Al-