Ulsan keep alive hopes of retaining ACL crown while Nagoya advance in thriller

Defending champions Ulsan Hyundai have kept alive their title defence in the 2021 AFC Champions League after booking a place in the quarterfinals of the continental competition with a penalty shootout victory over Kawasaki Frontale at the Ulsan Munsu Football Stadium.

Elsewhere, Japan's Nagoya Grampus produced a second-half resurgence to down South Korea's Daegu FC after a six-goal thriller in another last-16 clash on Tuesday. Monday's sole match saw 2019 champions Al Hilal become the first team through to the last eight when they eased past Iran's Esteghlal with a 2-0 win at the Zabeel Stadium in Dubai.

Here are the things we learned from the Round of 16 matches in the ACL so far.

Ulsan's title defence alive after cagey clash but they need more in attack

The battle between South Korea's Ulsan and Japan's Kawasaki was touted as one of the standout fixtures of the Round of 16 of the AFC Champions League this season -- with the matchup pitting the league leaders from their respective countries for a berth in the quarters.

Ulsan and Kawasaki have been in scintillating form in their domestic leagues, and the two teams had also recorded six wins out of six in the group stages in the Champions League. And as often is the case in such high stakes knockout fixtures, the football turned out to be a cagey affair in Ulsan.

There was nothing to separate the two sides -- in 90 minutes of regular action and then 30 minutes of extra time. Jo Hyeon-woo and Jung Sung-ryong, the two South Korean shot-stoppers guarding the goals for Ulsan and Kawasaki respectively, proved to be the stars of the evening. Both kept the game goalless before Jo made the critical save in the tie-breaking shootout that led to Ulsan's win.

Ulsan have found goals hard to come by in Asia this season even when they maintained a perfect record in the group stage. And that area will be something that head coach Hong Myung-bo will look to improve on before the Horangi take to the field for their quarter final clash in October.

Swierczok the new hero for Nagoya while Daegu miss Jeong

Nagoya have a new hero in Jakub Swierczok after the Poland international struck a hat-trick to help the Japanese side claim a thrilling victory over Daegu 4-2 at the Toyota Stadium, and progress to the quarterfinals of the competition for only the second time in their history.

Daegu, making only their second appearance in Asia, struck first on Tuesday with Cesinha netting in the fourth minute. In a sign of things to come, Swierczok levelled the affair just eight minutes later with a smart finish.

The K League 1 side once again went ahead when Jeong Tae-wook's cross was headed in by Edgar Silva in the 28th minute. But an injury to centre-back Jeong, forcing him to be substituted in the first half, essentially took the wheels off Daegu's challenge.

Swierczok, who was acquired from Piast Gliwice in July and had only netted once in five J1 League matches so far, took the spotlight in the second half as he headed in the equaliser in the 63rd minute before completing his treble two minutes later.

Nagoya were imperious in the final half an hour of the Round of 16 tie and captain Shinnosuke Nakatani put the result beyond doubt 11 minutes from time. The Japanese side will aim to book a first semifinal since 2009 when they return to the competition next month.

Al Hilal poised to challenge again after 2020 COVID-19 setback

The disappointment of the 2020 Champions League campaign is still fresh in the minds of players and supporters of Al Hilal. The Saudi Arabian giants had looked strong as they went in to defend their continental crown, but little did they know it was going to end in a catastrophe.

A COVID-19 outbreak in the camp took out one player after the other so much so that they were kicked out after failing to name a minimum of 13 players for their fourth group fixture. It was a huge blow for the Saudis who had recorded three straight wins by then.

However, signs are that Al Hilal are in it to win it this year. They did not have the most convincing of group-stage campaigns at home in 2021, but they have now made a statement victory by knocking out Iran's Esteghlal, who had emerged winners of a tough group featuring Al Duhail, Al Ahli and Al Shorta.

Matheus Pereira, who arrived from West Brom on a £16 million transfer following their relegation from the Premier League, created the opener by sending Bafetimbi Gomis on his way to breaking the deadlock in the 39th minute, before Salem Al-Dawsari sealed the win after the restart and proved they will be a force to reckon with in the quarterfinal.