Both Sweden and Ukraine registered victories against Denmark and Slovenia respectively though the Danes will be the happier of the two after scoring an away goal.
In Solna, Paris Saint-Germain star Zlatan Ibrahimovic scored his ninth goal in as many qualifiers in the 2-1 win.
Ibrahimovic converted a second half penalty after Emil Forsberg had scored his first international goal on the stroke of half-time.
Substitute Nicolai Jorgensen got Denmark’s goal 10 minutes from time to set up an intriguing tussle in Copenhagen on Tuesday.
“We feel satisfied with the result,” said Forsberg after the game. “Obviously 2-0 would have been better than 2-1 but we won and we’ll take that slight advantage into the next game.”
The Denmark goalkeeper Kaspar Schmeichel said he was optimistic that his side could still progress. “We got the away goal and that could prove crucial after the next match,” he added.
In Lviv, Ukraine beat Slovenia 2-0. Andrei Yarmolenko and Yevhen Seleznyov were the Ukraine heroes. Yarmolenko opened the scoring mid way through the first half.
Slovenia goalkeeper Samir Handanovic failed to clear Yevhen Konoplyanka's cross, Yarmolenko picked up the rebound and slotted inside the far post with a low shot
There was further joy for the partisans nine minutes after the pause when Seleznyov got the second with a close range shot.
Even with their two goal advantage ahead of the return leg in Maribor on Tuesday, the Ukrainians will be wary. They’ve lost all five of their previous qualifying play-offs for major tournaments.