Udinese claimed Italy's final Champions League berth following a 0-0 draw with AC Milan on Sunday that concluded the Serie A season.
The northeastern club finished level on points with Lazio but took fourth place since it held the tiebreaker over the Roman club on goal difference.
Lazio settled for the Europa League following a 4-2 win at Lecce and city rival Roma took the final Europa League spot following a 3-1 win over Sampdoria.
Juventus, which was still hoping to qualify for Europe, missed out following a 2-2 draw with Napoli at home.
Udinese will still have to play the final preliminary round to qualify for the Champions League. It last qualified for the elite competition six years ago when it also finished fourth.
After getting through the final preliminary round in the 2005-06 season, Udinese failed to advance from a group that contained eventual champion Barcelona.
Milan, which sealed the Serie A title two weeks ago, Inter Milan and Napoli had already gained direct qualification to the Champions League. Palermo also received a Europa League spot by reaching next weekend's Italian Cup final against Inter.
Sampdoria, Brescia and Bari were each already relegated.
Earlier, Giampaolo Pazzini scored twice and Japan fullback Yuto Nagatomo added another as Inter beat Catania 3-1 at the San Siro.
Palermo was beaten 3-1 at home by Chievo Verona.
Elsewhere, last-place Bari won 4-0 in Bologna with a hat trick from 18-year-old forward Francesco Grandolfo, who was playing his third match in the top division. Still, Bari will be in Serie B next season.
Also, it was: Brescia 2, Fiorentina 2; Cagliari 1, Parma 1; and Genoa 3, Cesena 2.
At the Stadio Friuli, Udinese hit the goalframe on three different occasions.
Antonio Di Natale hit the post with a free kick in the 19th minute, then had a penalty shot deflected by Milan goalkeeper Marco Amelia that hit the post in the 74th.
Di Natale still ended the season on top of the Serie A scoring chart with 28 goals, two more than Napoli's Edinson Cavani.
Udinese's other chance came in the 77th, when a long shot from Gokhan Inler ricocheted off both the crossbar and post before deflecting away.
Milan had little to play for but was concerned when striker Alexandre Pato was carried off on a stretcher in the 71st with an apparent right shoulder injury.
While Udinese celebrated to the tune of the Champions League music at the final whistle, Milan players bid midfielder Andrea Pirlo goodbye by repeatedly launching him up into the air.
Pirlo announced last week that he is leaving the club after 10 memorable seasons.
In Lecce, which had already staved off relegation, Mauro Zarate scored twice for Lazio after captain Tommaso Rocchi had opened the scoring. Giuseppe Vives added an own goal for the Roman club after Lecce had been reduced to 10 men when goalkeeper Massimiliano Benassi was sent off for tripping Rocchi, leading to a penalty converted by Zarate.
At the Stadio Olimpico, Daniele Manini put Sampdoria ahead before Roma responded with goals from forwards Francesco Totti, Mirko Vucinic and Marco Borriello.
Juventus fell behind twice when Christian Maggio and Cristiano Lucarelli scored for Napoli, but the Turin club equalized each time with goals from Giorgio Chiellini and Alessandro Matri.
In Milan, Pazzini found the target in the 15th and 48th - his second coming following a cross from Diego Milito - to raise his scoring total to 11 league goals since transferring from Sampdoria in January.
Nagatomo made it 3-0 in the 63rd with a rising angled shot from within the area, his second score of the season, and Pablo Ledesma pulled one back for Catania in the 66th.
The five-time defending champion, Inter was already secure of finishing second.
