The in-form midfielder hit the second goal on 76 minutes as Greece beat Cyprus 2-0 in Group B.
Iceland know that victory in their final match in Norway on Tuesday will secure second place. Gylfi was substituted on 82 minutes.
Christian Eriksen struck the woodwork as Denmark came within seconds of toppling leaders Italy in Group B.
The midfielder's free-kick hit the crossbar with the score at 1-1 but Nicklas Bendtner soon bagged his second goal to put the Danes 2-1 up. However, Alberto Aquilani equalised in added time.
Denmark can still make the play-offs from Group B but four teams can still finish second - Denmark, Bulgaria, Czech Republic and Armenia.
The Danes look to have the easiest task though as they face bottom-team Malta on Tuesday.
Vlad Chiriches also has hopes of a place in the play-offs after Romania's 4-0 win against Andorra. Vlad completed the 90 minutes and was brought down for a penalty for Romania's third goal.
Romania and Turkey are level on points in Group D - Turkey sit second, thanks to a better goal difference - but Turkey travel to Holland in their final match on Tuesday, while Romania take on Estonia. Holland top the group with eight wins in nine and hammered Hungary 8-1 on Friday. Estonia are one off the bottom.
Hugo Lloris' France are now three points behind Spain in Group I. Spain beat Belarus on Friday night and are favourites with a home match remaining against Georgia on Tuesday. France take on Belarus on Tuesday and will look set for the play-offs.
Meanwhile, Hugo played 90 minutes as France hammered Australia 6-0 in a friendly on Friday night.
Elsewhere, as we've already reported, Belgium made it to the next summer's finals in Brazil and Andros Townsend inspired England's key victory against Montenegro.
In South America, Erik Lamela came on for the last 10 minutes of Argentina's 3-1 win against Peru. They top South American qualifying by five points from Colombia with a final qualifier against Uruguay to follow on Tuesday and are already preparing for Brazil, 2014.
Paulinho played 70 minutes for Brazil in their 2-0 friendly win against South Korea in Seoul on Saturday. The midfielder set-up the second goal, scored by Oscar.
Aaron McEneff played 82 minutes as Northern Ireland grabbed a late draw against France in European U19 qualifying on Saturday.