Paraguay deny Sven winning start
Didier Drogba gave the Elephants the lead early in the second half and former England coach Eriksson, taking charge for the first time less than two weeks before the start of the World Cup, looked set to celebrate a win when substitute Souleymane Bamba made it 2-0.
Argentine-born Lucas Barrios pulled one back with his second goal in as many appearances for the South Americans, who began with a second string line-up, and Aureliano Torres snatched a last-gasp equaliser with a deflected free kick
Ivory Coast face Brazil, Portugal and North Korea in their World Cup group while Paraguay meet Italy, New Zealand and Slovakia.
The match was played at the home of French third division champions Evian, a stadium which has already been ruled unfit for second division games next season by the French league.
The substitutes' benches were too small for the delegations and the Paraguayan reserves watched the match among the crowd in the only stand, with a superb view over Lake Geneva.
It had been switched to the ground at only 48 hours notice after the pitch at the scheduled venue in nearby Thonon-Les-Bains was declared unfit after hosting a rugby festival only days before.
The Africans, wearing a bizarre strip of light blue shirts and chocolate-coloured shorts and socks, looked as if they had waded through mud before taking the field.
"I think we did well it the first half and the beginning of second half, probably we should have scored more goals," said Eriksson.
"We created a lot of chances, in the last 30 minutes we lost organisation in our team, we didn't keep possession as well.
"We have to play better, we will play better, we have worked one week with all the players. It's about organisation, defending well together, attacking well together, we're working every day on that."
The Ivorians gradually took control in a rough first half.
Aruna Dindane shot wide after bursting through the Paraguay defence but the best first-half chance fell to Drogba, who dived in to meet Chiek Ismael Tiote's cross but directed his header just wide of the goal.
Paulo da Silva also did well to block a Drogba shot just before the break.
Drogba's persistence paid off when he scored with a free kick in the 54th minute, a deflection wrong-footing Villar.
Gervais Yao Kouassi was close to a second when his effort was blocked by Villar but Ivory Coast increased their lead in the 74th minute when Bamba volleyed in from a free kick at the far post.
Paraguay came to life following the entrance of Roque Santa Cruz and Barrios, with the Borussia Dortmund striker pulling one back two minutes later.
Barrios should have equalised shortly afterwards when he broke through and rounded Boubacar Barry only to see his shot blocked by a defender.
But Torres did snatch the equaliser with a deflected free kick with one minute left.