Ecuador secured an unlikely victory to send the semi-finalists of France '98 tumbling out of the World Cup.
With Italy drawing against Mexico in the other Group G game, victory would have taken Croatia through to the second round.
But they turned in a sluggish performance against a side who had lost their opening two games and Ecuador fully deserved their win.
Striker Edison Mendez scored the crucial goal early in the second-half, sending an imperious half-volley past Stipe Pletikosa in the Croatian goal.
Croatia finally came alive in the closing stages but they were made to pay for their complacent start.
Mirko Jozic's side had gained a confidence-boosting draw against Italy in their previous game.
But it was Ecuador who enjoyed the better of the early play and Mendez tested Pletikosa with a powerful 30-yard shot.
Milan Rapaic and Alen Boksic started to become more influential as the half went on though.
Middlesbrough striker Boksic turned sharly inside the area and shaved the outside of the post with a left-footed shot after half-an-hour.
Croatia's Alen Boksic rues a missed chance
Minutes later he was played one-on-one with Jose Cevallos before being denied by a fabulous last-ditch tackle from Ivan Hurtado.
On the cusp of the interval Boksic enjoyed his third good chance of the half.
Rapaic, the cultured Fenerbahce midfielder with a lethal left foot, played an imperious long ball to Boksic, who hit the ball over Cevallos's head, only for Augusto Poroso to head out for a corner.
Croatia may have been the stronger side at the end of the first half, but it was Ecuador who struck the lethal blow at the start of the second.
Southampton striker Agustin Delgado headed into the path of Mendez, who struck a searing half-volley past Pletikosa.
We knew we had no real chance of qualifying but we can now leave with our heads held high
Croatia piled forward in search of an equaliser in the closing stages and at last started to play some impressive football.
Davor Vugrinec had a good chance in the closing minutes but fired over the crossbar and Ecuador defender Alex Aguinaga blocked an Ivica Olic header on the line at the death.
Ecuador: Cevallos, De la Cruz, Hurtado, Guerron, Marlon Ayovi, Mendez, Obregon (Aguinaga 40), Poroso, Carlos Tenorio (Kaviedes 76), Chala, Delgado.
Subs Not Used: Ascensio, Walter Ayovi, Burbano, Espinoza, Fernandez, Gomes, Ibarra, Sanchez, Edwin Tenorio, Viteri.
Goals: Mendez 48.
Croatia: Pletikosa, Simunic, Tomas, Simic (Vugrinec 52), Robert Kovac, Jarni, Niko Kovac (Vranjes 59), Saric (Stanic 67), Rapaic, Olic, Boksic.
Subs Not Used: Balaban, Butina, Prosinecki, Seric, Soldo, Suker, Vasilj, Vlaovic, Zivkovic.
Booked: Tomas, Simunic.
Referee: William Mattus Vega (Costa Rica).
MATCH STATS |
| Ecuador | Croatia |
Corners (1st half) | 3 | 3 |
Corners (2nd half) | 1 | 5 |
Fouls committed | 18 | 18 |
Caught offside | 2 | 3 |
Shots on target | 5 | 6 |
Shots off target | 6 | 7 |
Hit woodwork (back into play) | 0 | 1 |
Yellow cards | 1 | 2 |
Red cards | 0 | 0 |
STOPPAGE TIME | |
First half - 1 min | Second half - 2 mins |