The South Americans have had a superb start to the tournament, easily beating hosts Qatar 2-0 before outplaying the Netherlands and being unfortunate not to win in a 1-1 draw that made a mockery of the gulf in their world rankings.

The job is not done, however, as defeat by African champions Senegal could send them home rather than enable them to reach the knockout round for the second time in Ecuador's history.

"We have a bigger battle coming," coach Gustavo Alvaro quickly warned after the euphoria of the performance against the Dutch, whom he had craftily acknowledged in advance were a superior side.

So far, Ecuador have been reliant on their veteran striker Enner Valencia, who has scored all their goals to add to his three at the 2014 World Cup.

But he is only the spearhead with a wealth of exuberant talent behind him, not least flourishing young midfielder Moises Caicedo, 21, who is at the heart of everything good that Ecuador do, both shielding his defence and releasing the strikers.

Once again, Ecuador are sweating on Valencia's fitness after he was stretchered off late on in the Netherlands game with a recurrence of a knee strain suffered against Qatar.

"He's the only one with World Cup experience," said Alfaro, who led a generational change in the national side that enabled them to punch their way out of arguably the world's toughest qualifiers in South America.

"The rest are kids."

Senegal are less intimidating opposition without the injured Sadio Mane and know they have to improve to beat Ecuador after losing 2-0 to the Dutch but beating Qatar 3-1 to sit in third place in Group A on three points.

"Our concentration must be better," said Senegal coach Aliou Cisse. "We need to win to have a chance to qualify for the last 16."

One of only three African nations to have reached the quarter-finals of a World Cup, Senegal know that victory over Ecuador would help atone for a miserable last tournament in Russia where they were eliminated on disciplinary points.

Senegal could theoretically still go through if they draw, as could Ecuador if they lose, but both those scenarios would require a win by Qatar over the Netherlands sufficient to push the Dutch into third place on goal difference.

Australian Associated Press