Korea Republic maintained their stunning 2010 AFC Champions League form with all four of their participants advancing to the last eight to record a clean sweep in east Asia. In doing so they made history with 2010 being the first occasion four teams from one nation have reached the competition’s quarter-final stage.

While the Koreans will be optimistic of top spot on the podium later this year, there have been mixed fortunes for previous winners during this year's campaign. After inaugural champions Al Ain, and two-time winners Al Ittihad, failed to progress beyond the group stage, 2008 victors Gamba Osaka found themselves eliminated following a surprisingly one-sided 3-0 loss against Seongnam Ilhwa. However defending champions Pohang Steelers scraped through with a solitary-goal triumph at Kashima Antlers, while 2006 winners Jeonbuk Motors needed extra time to overcame hosts Adelaide United by the odd goal in five.

In the west, Saudi Arabia stole the show with high-flying Al Hilal crushing Bunyodkor 3-0 to progress while Al Shabab came from behind to knock out Esteghlal 3-2. Qatar’s Al Gharafa and Zob Ahan of Iran also went through after defeating Pakhtakor and Mes Kerman with 1-0 scorelines. The draw for the knockout stage will take place on 25 May.

The game
Adelaide United 2-3 (extra time) Jeonbuk Motors
Goals: Robert Cornthwaite 78, Sergio van Dijk 90+5; Eninho 38, 87, Lee Dong-Gook 116
The two sides began tentatively and following a cagey start Jeonbuk were the first to attack, Choi Tae-Uk testing the Adelaide keeper Eugene Galekovic with a distant shot. The K-League champions' efforts paid dividends seven minutes from break when Brazilian hitman Eninho finished off a move he initiated. Roared on by the home crowd, the Reds hit back with both Travis Dodd and Daniel Mullen close to netting the equaliser but it did not come until the 78th minute when Robert Cornthwaite popped up to pull them level.

With just three minutes remaining, Eninho appeared to have grabbed the winner, but once again the hosts equalised in dramatic fashion. Dutchman Sergio van Dijk bundling the ball over the line deep into injury time to force the game into the extra half-hour. Adelaide were then twice denied by the woodwork with Cássio rattling the post before Adam Hughes's free-kick crashed against the crossbar, while Jeonbuk's Lee Dong-Guk also saw his header bouncing off the bar. However, the Korean international had the final say when he latched onto Park Won-Jae's pass to seal an action-packed win.

The surprise
Al Hilal 3-0 Bunyodkor
Goals: Majed Al Marshadi 9, Christian Wilhelmsson 57, Thiago Neves 61
The much-anticipated contest between two of the tournament favourites ended in surprise with Al Hilal putting three unanswered goals past Luiz Felipe Scolari’s charges. Eric Gerets' home team got off to an ideal start when Majed Al Marshadi got his head onto Thiago Neves' pass after nine minutes. The goal spurred the visitors into action but their profligacy in front of goal proved costly as the hosts eventually doubled their lead through Christian Wilhelmsson after the interval. The Swedish midfielder then turned provider when he set Neves up for the clinching goal.

The other headline-grabbers
Playing away at Seongnam Ilhwa, Gamba Osaka stayed in touch with their Korean hosts in a goalless opening half but their game plan fell to pieces when the K-League giants took the lead on 74 minutes thanks to a penalty from Colombian midfielder Mauricio Molina. Second-half substitute Song Ho-Young doubled the lead six minutes later before Molina added his second with a free-kick in injury time.

Although languishing in the lower depths of the K-league, Suwon Bluewings came good on the Asian stage against China’s Beijing Guoan with Jose Mota the two-goal hero. After heading the hosts ahead on 27 minutes, the Brazilian striker coolly finished Yeom Ki-Hun’s cross six minutes from time.

Despite being the only team to finish the group campaign with a 100 per cent record, Kashima Antlers fell flat in the knockout stage as they went down to Pohang Steelers with Mota scoring the only goal. Elsewhere, Al Gharafa had to wait until an 84th minute penalty to get the better of Pakhtakor, while there was also a late winner for Zob Ahan against Mes Kerman in an all-Iranian affair.

The player
Jose Mota has proved to be Suwon’s most valued import with his prolific form in Asia’s premier club competition. A brace against Beijing took his season tally to nine and has the Brazilian at the top of the tournament’s goalscorers chart.

The stat
of this round’s 21 goals were claimed by Brazilian imports in what has become a common theme in recent seasons of the competition.

What they said
"I didn't make big changes to what the ex-coach had done but I focused on bringing last year's form back to the team. With the players rediscovering their old selves, we can go further ahead in both Asia and the home front." Pohang Steelers caretaker coach Park Chang-Hyun

2010 AFC Champions League Round of 16 results
11 May
Al Gharafa (QAT) 1-0 Pakhtakor (UZB)
Suwon Bluewings (KOR) 2-0 Beijing Guoan (CHN)
Seongnam Ilhwa (KOR) 3-0 Gamba Osaka (JPN)
Al Shabab (KSA) 3-2 Esteghlal (IRN)

12 May
Kashima Antlers (JPN) 0-1 Pohang Steelers (KOR)
Zob Ahan (IRN) 1-0 Mes Kerman (IRN)
Adelaide United (AUS) 2-3 ET Jeonbuk Motors (KOR)
Al Hilal (KSA) 3-0 Bunyodkor (UZB)