A brilliant block tackle by Valon Behrami in his own area instigated the break, which was allowed to continue by an excellent decision from Uzbek referee Ravshan Irmatov after the midfielder was body-checked.
The move continued with Ricardo Rodriguez crossing for Seferovic to finish in the 93rd minute, sending the Swiss fans into raptures and deflating the South Americans, who had played their part in another World Cup attack-fest – albeit lacking the quality seen in earlier matches.
“It was a dream end to the game for us and is very important for the morale of the team,” Swiss coach Ottmar Hitzfeld told reporters.
“It will give us some extra strength for the next two matches,” he added, looking ahead to clashes with France and Honduras.
The Swiss had promised more attacking endeavour with an exciting young side after dour, defensive displays in their last two World Cups, but it was the South Americans who struck first in the 22nd minute after pre-match concerns about the Europeans’ soft centre proved founded.
Ecuador striker Enner Valencia easily stepped away from Johan Djourou to meet Walter Ayovi’s free kick from the right and Swiss goalkeeper Diego Benaglio was stuck on his line as the ball fizzed into his six-yard box.
The Swiss had bossed possession for long periods at the Brasilia national stadium, where thousands of fans missed the kickoff as the negotiated the lengthy security queues, but they struggled to break down the South Americans and were restricted to long shots.
Hitzfeld had seen enough and opted to introduce Admir Mehmedi at the break and the forward needed just three minutes to make an impact as he beat Carlos Gruezo to head home a corner and level the scores.
The goal opened up the scrappy but entertaining contest as the play flowed end to end but both teams lacked calmness and quality in the final third.
The Swiss, who beat Spain in their opening match in South Africa four years ago but failed to reach the knockout stages, thought they had taken the lead when Josip Drmic poked home from close range with 20 minutes left but the strike was wrongly ruled out for offside.
Undeterred, both sides continued to go toe to toe like heavyweight boxers and Ecuador substitute Michael Arroyo almost snatched the lead with an 86th-minute deflected free kick that unconvincing Swiss goalkeeper Diego Benaglio did well to palm away.
The Ecuador substitute was then guilty of dawdling in possession after trying to take an extra touch in the penalty area when he should have shot, allowing Behrami, who was guilty of giving away the ball cheaply throughout the match, to block his effort in the dying seconds.
The fatigued South Americans were slow to track back after committing forward in search of the winner with Rodriguez allowed time and space down the left to roll his cross into the area for Seferovic to smash into the roof of the net.
Ecuador coach Reinaldo Rueda lamented “a moment of naivety” that cost his side the game. “We lost our organisation at the end, we were somewhat betrayed by our emotion and this provoked the goal which took the draw away from us,” he told reporters.
(Editing by Ed Osmond)