SEOUL, South Korea?- FC Seoul, Buriram United, Al Shabab and 2012 finalist Al Ahli advanced to the Asian Champions League?quarterfinals on Tuesday.

Seoul scored three second-half goals to beat Beijing?Guoan 3-1 on the night and by the same?margin overall to qualify for the quarterfinals for the third time in five years. Buriram drew 0-0 with Bunyodkor but won 2-1 at home last week, becoming the first Thai team to reach the last eight in 10 years.

Sebastian Tagliabue scored twice and Mohannad Assiri added a third goal in stoppage time as Saudi team Al Shabab beat Al Gharafa of Qatar 3-0 for a 5-1 total on aggregate, progressing to the quarterfinals for the first time since reaching the 2010 semifinals.

Al Ahli's 2-0 victory over El Jaish gave the Saudi team a 3-1 aggregate win.

The round of 16 will be completed when the four remaining matches are played Wednesday.

At Seoul, Beijing opened the scoring in the ninth minute through French striker Fred Kanoute. Adilson Dos Santos equalized after an hour, and the K-League champions took the lead in the 70th minute through Yun Il-lok's shot from close range. Koh Myong-jin secured the victory in stoppage time.

Beijing finished with nine men after Kanoute and midfielder Zhang Xinxin picked up second yellow cards in the last 10 minutes. Adilson was sent off after his second booking in the 87th.

"Our performance in the second half was remarkable," Seoul coach Choi Yong-soo said. "The big challenge begins now and we will prepare well to ensure we finish on top."

In Tashkent, Buriram became the first Thai side since inaugural finalist BEC Tero Sasana in 2003 to reach the quarters after getting past the two-time semifinalists from Uzbekistan.

"A goalless draw was enough for us to continue in the competition. We had some chances to score, but we couldn't. But I am pleased with the way we defended," Buriram coach ScottCooper said.

With time running out, Bunyodkor increased the pressure but was unable to find a way past the defense.

"We had our chances to win but Buriram played well defensively, "Bunyodkor coach Mirdjajal Kasimov said. "We also missed many chances and we are the only ones to blame for the result."

In Riyadh, Tagliabue beat advancing goalkeeper Qasem Burhan to open the scoring for Al Shabab in the 35th minute and scored a second from the edge of the six-yard area in the 48th. The Argentine striker finished as the Saudi league's top scorer this season with 19 goals.

Assiri went on as a substitute late in the second half and scored minutes later.

Al Ahli, last year's finalist, led 1-0 through Bruno Cesar's left-foot shot in the 24th minute. Mustafa Al Bassas doubled the advantage not long before the break when he drove his shot into the far corner.

Cesar had a chance to score his second from the penalty spot but goalkeeper Ahmed Sofyan was too good.