Kim Do-hoon’s side can now look forward to Sunday’s semi-final against Japan’s Vissel Kobe - who defeated Suwon Samsung Bluewings on penalties in the later quarter-final - while Beijing’s best-ever AFC Champions League showing ends at the quarter-final stage.
In a match pitting the competition’s prolific attack against its sturdiest defence, a passage of play involving Ulsan’s star striker and Beijing’s top defender produced the early part of the game’s defining moment.
It came when Junior’s improvised, acrobatic volley caught the hand of Beijing’s Korean defender Kim Min-jae, with the Video Assistant Referee, in use for the first time during the AFC Champions League (East), awarding a penalty kick, which Junior successfully converted in the 21st minute.
Trailing, but with Renato Augusto, Jonathan Viera and Fernando pulling the strings, Beijing had most of the possession and shots at goal in a hard-fought but high-quality opening 45 minutes, but they found themselves with a two-goal mountain to climb at half-time after a moment of brilliance from Junior.
Having already netted his penalty, the Brazilian striker this time showed his quality from much further out in the 42nd minute - sending a scorching strike past Beijing goalkeeper Hou Sen from all of 30 yards for his second goal of the match, his fourth of the tournament and his 30th of the season in all competitions.
Now in unchartered territory in what had been an unbeaten campaign, Beijing emerged with renewed intensity after the interval.
Renato, Fernando and A Lan were involved in their best move of the match in the 52nd minute, although goalkeeper Jo Su-huk made one of eight saves to keep the latter’s low effort out, and Viera rattled a shot against the upright 10 minutes later as Bruno Génésio’s side raised the tempo.
Beijing had more than 20 attempts at goal, but Ulsan were equal to the task. Committed defending from Dave Bulthuis and Park Joo-ho saw three successive Beijing shots at goal blocked with just over 20 minutes remaining, and the Chinese side’s fate was sealed with substitute Zhang Yuning missing the target from 10 yards in the shadows of full time.
Ulsan’s win keeps alive their bid for a second Asian title. They won the AFC Champions League for the first time in 2012.