Portugal won 3-0 in post-match penalties against Slovenia.
Ronaldo missed an extra-time penalty but recovered to help Portugal win 3-0 in penalties.
Denmark will play England in their second Group C game in Frankfurt on Thursday.
Algeria and Slovenia signed on Monday several cooperation agreements, including a deal to boost Algeria's gas exports to Slovenia, Algeria's official APS news agency reported.
Slovenian President Natasa Pirc Musar called for open borders at a Monday meeting of regional leaders, which celebrated 20 years of Slovenia's accession to the European Union.
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