The scrambled goal, three minutes into second-half injury time, helped struggling Argentina scrape by Peru 2-1 on Saturday. That means the two-time champions will reach next year's World Cup in South Africa if they can win on Wednesday in the final round of qualifying at bitter rival Uruguay.
Anything less and they could face a playoff - or be out altogether. Chile avoided the drama, winning 4-2 at Colombia to claim the third of four automatic qualifying spots from South America for its World Cup appearance since 1998.
Colombia was eliminated. Waldo Ponce, Humberto Suazo, Jorge Valdivia and Fabian Orellana scored for Chile.
Uruguay kept its World Cup hopes alive, winning 2-1 in Quito at 2,800 meters after Diego Forlan converted a penalty in the fourth minute of injury time. Uruguay will also advance automatically if it beats Argentina on Wednesday in Montevideo.
In the day's other match, Paraguay won 2-1 at Venezuela thanks to second-half goals by Salvador Cabanas and Oscar Cardozo.
Brazil, Chile and Paraguay have qualified with one round to play on Wednesday. The fourth-place team also gets an automatic berth, and No. 5 faces a playoff in November with the No. 4 from North and Central America and the Caribbean.
Teams finishing sixth or worse are out.
Argentina has 25 points in fourth place followed by Uruguay with 24, Ecuador with 23 and Venezuela with 21.
Argentina played poorly despite fielding many of the world's best players, but escaped with the late victory. That will take some pressure off embattled coach Maradona, but it may leave the two-time champions needing another "miracle" to defeat Uruguay.
Palermo scored from close-in on a scrambled play in the final seconds as a driving rain soaked the field. And it drenched Palermo, too, who ripped off his shirt and raised his arms to the heavens to celebrate the winning goal at River Plate's Monumental stadium.
"Go and put and end to this story just as you have so many others," Maradona said he told Palermo, as he sent him into the game in the 48th minute with the game at 0-0.
Peru's Hernan Rengifo leveled the match with about 20 seconds left in regulation time after Real Madrid striker Gonzalo Higuain put Argentina ahead in the 48th - just seconds after Palermo entered - on a sharp-angled shot from six meters.
"We're going to go play in Montevideo (Uruguay) with all of our pride," Maradona said.
Peru has the worst record in South American qualifying with only two victories in 17 games - and only 10 goals scored. Peru has never won a match in Argentina.
Of the 11 players who started the last qualifier for Argentina - a 1-0 loss to Paraguay - only four started against Peru. Maradona shuffled his lineup, which he has done constantly since taking over a year ago. He's used 76 players in that span.
Higuain was one of three players making his debut for Argentina. Defender Emiliano Insua and midfielder Enzo Perez were also playing their first games.