Ten-man Iceland battled to 0-0 home draw with Croatia in Reykjavic to keep alive their dream of qualifying for a first major tournament while Greece will be confident of finishing off Romania next week after a 3-1 victory in Athens.
Of the eight European nations in the last-chance saloon after missing out on automatic passage to next year's tournament in Brazil, France are the worst placed going into next week's second legs after a miserable night in Kiev.
Second-half goals by Ukraine's Roman Zozulia and Andriy Yarmolenko and a red card for France defender Laurent Koscielny made it a night to forget for Didier Deschamps' side who need a vast improvement in Paris on Tuesday to repair the damage.
"It's obviously a very bad result. We have to believe (we can go through) but Ukraine are the team in the best position to qualify," he said.
France last failed to reach a major tournament in 1994 but Deschamps, who was past of that squad, remained defiant.
"We still have 90 minutes at home," he added.
FIFA Ballon d'Or nominee Franck Ribery was shackled closely as Les Blues toiled at the Olympic Stadium.
A draw would have been a satisfactory result to take home but just past the hour Zozulia squeezed a shot under Hugo Lloris from close range to spark wild celebrations.
Koscielny then fouled Zozulia in the box to allow Ukraine to double their lead and the Arsenal man's frustration boiled over when he slapped Kucher in the face to earn a red card that will keep him out of the return match in Paris.
Ukraine also finished with 10 men after Kucher was dismissed for a second yellow card for a foul on Ribery.
Ronaldo overshadowed Sweden's Zlatan Ibrahimovic in their playoff match - billed as a clash between two of Europe's hottest strikers - pouncing late on a tense night in Lisbon.
By a quirk of the draw for the playoffs, one of the biggest names in the world game will be missing next year in South America - a blow for neutrals and sponsors alike.
However, the odds look slightly shorter on Ronaldo gracing the stage after the Real Madrid man, so often the dazzler, proved he will also put his head in the line of danger for his country by stooping to score an 82nd minute winner.
He also struck the woodwork shortly afterwards as Portugal sought the comfort of a second goal.
As it is, a workmanlike Swedish side still harbour high hopes of swinging the tie their way.
"We created a great early chance and Sweden hit back. But in the second half it was one way for us," Portugal coach Paulo Bento told reporters.
"It was an important step to reach the World Cup but not yet decisive."
Iceland played most of the second half with 10 men against Croatia after Olafur Skulason was shown a straight red card in the 50th minute but they hung on stubbornly for a draw.
"To defend for almost 45 minutes with one less man on the pitch... I can't describe in words what these players have done," Iceland coach Lars Lagerback said.
Swede Lagerbeck was annoyed by the decision to send off Skulason for tangling with Ivan Perisic, while Croatia coach Niko Kovac was also disappointed with his side's tactics.
"We resorted to playing long balls for too long," said the Croat. "I expected us to keep it on the ground more and we just didn't implement the gameplan."
Kostas Mitroglou struck twice for Greece in Athens with Dimitris Salpingidis also on target against the Romanians who had levelled through Bogdan Stancu.
Several countries spared the ordeal of a playoff were also in action as the build-up to the 2014 finals begins in earnest.
Italy and Germany drew 1-1 at the San Siro where Ignazio Abate grabbed his first international goal for the hosts after Mats Hummels put the visitors ahead on the night their coach Joachim Loew celebrated his 100th match in charge.
England were given a jolt at Wembley as an experimental side were outclassed by Chile, for whom Barcelona striker Alexis Sanchez scored twice in a convincing 2-0 win.
Italin Fabio Capello's Russia side were held 1-1 at home by Serbia while Switzerland went down 2-1 to South Korea in Seoul.
- Sports & Recreation
- Didier Deschamps