Rain and high winds lashed Vienna's Fan Zone -- an outside arena where supporters had gathered to watch the match -- as lightning forked the sky above, forcing police to evacuate 25,000 fans, CNN's Pedro Pinto reported.
Two people were badly hurt during the evacuation, including a woman who sustained back injuries, according to media reports.
Some fans tried sheltering against giant TV screens while others, caught up in the occasion, kicked floodwater over each other or played with footballs.
The match itself, being played in Basel, Switzerland -- the tournament's other co-host -- was unaffected by the severe weather.
However, the feed to TV stations worldwide was lost: only Swiss public TV and Al-Jazeera were unaffected, agency reports say.