Saudi Arabian duo Al Shabab and Al Ahli became the first teams to book their places in the knockout stage of the Asian Champions League with wins on Wednesday.
Sebastian Tagliabue's late breakaway goal secured a hard-fought 1-0 triumph for Al Shabab at Tractorsazi Tabriz to ensure their progress from Group A.
Al Ahli quickly followed their domestic rivals into the last 16 as teenager Mustafa Al Bassas' double inspired a 4-1 win at home to Sepahan in the late game.
Al Bassas grabbed the first two goals for last season's runners-up before a 67th-minute Bruno Cesar penalty made it 3-0. Radomir Dalovic grabbed a consolation for the Iranians but Bader Al Khames added a fourth in stoppage time.
Al Ahli have a perfect record in Group C and are set to be joined in the next round by Al Gharafa after the Qataris cast pointless Al Nasr aside 3-1.
Lawrence Quaye and Nene gave Al Gharafa control and, although Takayuki Morimoto replied, Fahd Al Shammari added a third 10 minutes from the end. The defeat means Walter Zenga's side became the first team to see their qualification hopes ended.
El Jaish lead the race for the second qualification spot in Group A after they drew 1-1 at Al Jazira.
Sultan Barghash opened the scoring for the home side midway through the first half but Brazilian striker Adriano equalised before the break.
Vegalta Sendai collected their first ever Champions League win as Atsushi Yanagisawa scored the only goal of the game against Group E leaders FC Seoul.
Vegalta were joined by Buriram United, two points behind Seoul, after the Thais beat Jiangsu Sainty 2-0.
Captain Suchao Nutnum and midfielder Charyl Chappuis scored the goals, although the latter was carried off on a stretcher with an apparent knee injury after celebrating his strike.
Bunyodkor moved clear in Group G with a 1-0 success at Beijing Guoan.
Fozil Musaev's close-range strike on 32 minutes inflicted a first defeat on Beijing, who slipped to third after Pohang Steelers were held 1-1 by Sanfrecce Hiroshima.
It was a first point of the campaign for the J.League champions, who opened the scoring against the run of play just after the hour through Naoki Ishihara.
Hwang Jin-sung quickly levelled, though, to leave Pohang two points adrift of leaders Bunyodkor.
Information from the Press Association was used in this report