Chile face a daunting trip to Ecuador on Thursday as they attempt to get their faltering 2018 World Cup qualification campaign back on track at a venue where they have never won.

After eight rounds of South America's marathon qualifying campaign, two-time Copa America champions Chile are languishing in seventh place, two points adrift of Ecuador in fifth.

The failure of Chile's star-studded squad to impose themselves on their rivals has been one of the biggest surprises of the qualifiers to date.

With back-to-back Copa America victories in 2015 and 2016, the Chileans have been the dominant force in competitive South American football in the past year.

However despite being able to call upon the likes of Alexis Sanchez, Arturo Vidal and Claudio Bravo, Chile have stumbled from one setback to the next so far.

Last month they were beaten 2-1 by Paraguay in Asuncion and were then held to a 0-0 draw by minnows Bolivia at home in Santiago.

While there is still plenty of time for Chile to turn their campaign around, they can ill afford to lose further ground in what is expected to be a tight battle for places.

Chile coach Juan Antonio Pizzi has recalled playmaker Jorge Valdivia following a 10-month exile while Bravo, Sanchez and Vidal are all expected to start at Quito's Estadio Olimpico Atahualpa, which is some 9,000 feet above sea level.

Chile, like many visitors to the stadium, have often struggled in the thin air and so far have not won a competitive fixture at the arena.

Ecuador, meanwhile, head into the game looking to rediscover their winning habit. After starting qualifiers with four straight wins, Ecuador have taken only one point from their last four games.

In other matches on Thursday, Uruguay will be confident of holding onto their position at the top of the standings when they face Venezuela in Montevideo, with star strikers Edinson Cavani and Luis Suarez both expected to play.

Venezuela are bottom of the 10-nation standings with no wins from eight games, although they gave Argentina a mighty scare in their last outing on September 6, taking a 2-0 lead before eventually being held for a 2-2 draw.

A resurgent Brazil meanwhile will attempt to extend the feelgood factor created by back-to-back wins over Ecuador and Colombia last month when they take on eighth-placed Bolivia in Natal.

Argentina, who are level with Brazil on 15 points but trail their rivals on goal difference, face an awkward trip to Lima to face Peru, with coach Edgardo Bauza mulling how best to plug the gap created by injury to captain Lionel Messi.

Messi returned from a short-lived retirement from international football last month to inspire a crucial 1-0 win over Uruguay, but is out of Thursday's game after suffering a groin injury while on Barcelona duty last month.

Bauza has indicated either Juventus's Paulo Dybala or Atletico Madrid's Angel Correa could start in Messi's place. "Either of them could do a job. I will see how they train this week and decide," Bauza said in Lima on Monday.

Argentina's Everton defender Ramiro Funes Mori meanwhile urged his team-mates to beware the threat posed by Peru's veteran striker Paolo Guerrero, the 32-year-old Flamengo attacker who is his country's all-time leading scorer with 27 goals in 73 games.

"We may be the favourites but you always have to be careful around a guy like Guerrero. He's a tricky player," the defender said.