While Senegal find themselves in a win-or-go-home scenario heading into this critical Group A encounter, surprise-package Ecuador needs just a point to progress to the Round of 16. Host-nation Qatar became the first team to be knocked out of this year's competition with their loss against Senegal last time out.
But it's all to play for in the last round of World Cup group stages, with the other three nations in Group A still in contention to progress to the next round. The Netherlands and Ecuador both are joint-top with four points, while Senegal are trailing a point adrift.
Senegal kept their hopes of making it to the last 16 alive with a nervy 3-1 victory against Qatar. They have endured a difficult campaign after losing talismanic striker Sadio Mane to injury only days before the World Cup, which came as a hammer blow Aliou Cisse's side's preparations.
Still, they gave a good account of themselves in their group opener against the Netherlands, but all their hard work was scuppered by two late goals from Cody Gakpo and Davy Klaassen to snatch away all three points.
But the Lions of Teranga bounced back with 3-1 nervy victory over minnows Qatar. A win in their final game will definitely see themselves qualify for the round of 16, but they come up against a strong Ecuadorian side that has been a surprise package in this year's World Cup edition.
The South American side are in prime position to book their spot in the last 16. After a comfortable win over Qatar, they dominated their second game against the Netherlands.
El Tri only got a point for their efforts, but Gustavo Alfaro's side impressed many by how they overran, neutralized their opponents, and produced decent opportunities for themselves.
As alluded above, there are high stakes in this clash, with only one of these nations likely to reach the knockout stages alongside the Netherlands, making for a tense affair on Tuesday, and the one who can control their nerves will likely qualify.
Ecuador vs Senegal confirmed lineups
Ecuador XI (4-3-3): Galíndez; Preciado, Torres, Hincapié, Estupiñán; Franco, Gruezo, Caicedo; Plata, Enner Valencia, Estrada
Senegal XI (4-2-3-1): Mendy; Sabaly, Koulibaly, Jakobs, Diallo; Ciss, P. Gueye; Ndiaye, I. Gueye, I. Sarr; Dia
Ecuador vs Senegal LIVE updates
Ecuador's upcoming fixtures
If Netherlands top Group A and Ecuador finish second, England are a possible opponent for in the next round, and their combination of talent, youthful exuberance, and pace could pose a threat to Gareth Southgate's side.
The Three Lions previously faced Ecuador in the knockout round in 2006, coming out as narrow 1-0 victors. A repeat could be on the cards, with this Ecuador side capable of giving pre-tournament favourites a run for their money.