Enner Valencia starts for Ecuador after overcoming a knee problem as his team battle Senegal on Tuesday for a World Cup last 16 place.

If the South Americans avoid defeat they will reach the next round, while Aliou Cisse's side, shorn of injured Bayern Munich forward Sadio Mane, are certain to progress if they triumph.

Should Ecuador not lose and better group leaders the Netherlands' result, they will finish top of Group A -- currently the Dutch lead on fair play points.

Coincidentally Senegal became the first team ever eliminated on fair play points at the 2018 World Cup.

Ecuador striker Valencia is the competition's joint top goalscorer with three and he has netted the country's last six goals in a row at the World Cup, including three in the 2014 edition.

After moving to a three centre-back system against the Netherlands in a 1-1 draw in which Ecuador impressed, coach Gustavo Alfaro has reverted to a four-man defence, as he set up in the opening day 2-0 win over eliminated hosts Qatar.

Carlos Gruezo starts in place of the suspended Jhegson Mendez, while Alan Franco starts for the first time in place of defender Jackson Porozo.

Cisse made three changes to the Senegal side which beat Qatar 3-1 last Friday, bringing in Pape Gueye, Pathe Ciss and Iliman Ndiaye.

Starting line-ups:

Ecuador (4-4-2)

Hernan Galindez; Angelo Preciado, Felix Torres, Piero Hincapie, Pervis Estupinan; Gonzalo Plata, Moises Caicedo, Carlos Gruezo, Alan Franco; Michael Estrada, Enner Valencia (capt)

Coach: Gustavo Alfaro (ARG)

Senegal (4-3-3)

Edouard Mendy; Youssouf Sabaly, Kalidou Koulibaly (capt), Abdou Diallo, Ismail Jakobs; Idrissa Gana Gueye, Pape Gueye, Pathe Ciss; Iliman Ndiaye, Boulaye Dia, Ismaila Sarr

Coach: Aliou Cisse (SEN)

Referee: Clement Turpin (FRA)