Argentina are in peril of missing their first World Cup since 1970 after they were held to a 0-0 draw against Peru.
Even a sell-out home crowd in Buenos Aires' La Bombonera was not enough to rally Lionel Messi's side, who slipped further from qualifying places.
Manager Jorge Sampaoli granted Boca Juniors striker Dario Benedetto his first full debut alongside Papu Gomez up front, although still it was not enough to invigorate the struggling team.
Argentina showed promise and controlled possession for opening stages of both halves, although Peru eventually found their stride.
Messi came tantalisingly close after finding himself on the receiving end of a corner midway into the first half, although a well-placed Peru defender sent his effort wide.
Another effort by Gomez was too high, while a curling shot by Messi approaching half time would have been artful had it found the back of the net.
Despite numerous, increasingly fraught, attempts to break the deadlock, the final whistle came and the stony faces of the hosts said it all.
Meanwhile a late winner by Arsenal forward Alexis Sanchez on international duty with Chile raised his side up above Argentina, who find themselves in sixth place with one game to go.
Only the top four teams in the South America group are guaranteed to be on their way to Russia next year, while the team that finish fifth will meet New Zealand for a two-legged playoff in November.
Argentina's fortunes largely rest on how other teams perform next week, when they will meet already-eliminated Ecuador who currently sit two places below in the table.
A win in Quito, which lies at nearly 2,900 metres above sea level, may throw Argentina a lifeline.