Tadaaki Hirakawa scored the all-important fifth penalty as Urawa became the first Japanese team to qualify for the final of Asia's premier club competition after goalkeeper Ryota Tsuzuki had earlier saved Choi Sung-kuk's spot-kick.

As a result, the J.League champions will face either Iran's Sepahan or Al Wahda of the United Arab Emirates in the two-legged final next month.

The game went into extra-time after finishing 4-4 on aggregate, the 2-2 scoreline after 90 minutes replicating the result in the first leg in Korea three weeks ago, thereby nullifying Reds' away-goals advantage.

Washington gave Reds the lead in the 21st minute only for Choi Sung-kuk to pull his side level in the 56th minute. Kim Dong-hun put Seongnam in front in the 69th minute but Makoto Hasebe restored parity four minutes later.

An additional 30 minutes could not separate the teams before Reds prevailed in front of a crowd of 51,651 with Hirakawa giving Seongnam goalkeeper Kim Yong-dae little chance with his perfectly placed penalty.

The win was a deserved one for a Reds side that went on the attack from the opening whistle and inside the first minute Washington could have given Holger Osieck's side the lead.

The Brazilian collected Hirakawa's cross with his back to goal before turning to hit a weak shot that caused Kim Yong-dae few problems.

Not to be outdone, Seongnam pushed forward too in an open first 10 minutes with Son Dae-ho firing off a long range effort that was only just wide of Ryota Tsuzuki's right post.

But after the initial flurry, matters started to tighten and the game became a pitch battle for control of the midfield.

Reds drew first blood, however, in the 21st minute when Washington's close control opened up the Seongnam defence as the Brazilian deftly steered a cross from compatriot Robson Ponte into the area before turning to lash his right-foot shot beyond the outstretched hand of Kim.

Urawa could have doubled their advantage with 12 minutes remaining in the half only for Ponte to mishit his close-range shot and within seconds Reds were almost made to pay when Yuki Abe was forced to hack Itamar's attempt clear after Tsuzuki had been drawn out of his goal.

Seongnam continued to look for the equaliser, with Choi Sung-kuk heading straight at Tsuzuki less than a minute later while at the other end Tatsuya Tanaka came close to finishing off a flowing Urawa move, only for his weak header to be easily collected by Kim.

Within 11 minutes of the restart, though, Seongnam pulled level. Itamar beat the Urawa defence single-handedly before pulling the ball back to Choi and the former Ulsan Hyundai striker slammed his shot into the roof of the net.

Ponte fired over the bar at the other end as Reds pushed to regain the lead, only for the J.League champions to be caught again in the 69th minute as Itamar caused more problems.

Tsuzuki parried the Brazilian's shot from the edge of the area and substitute Kim Dong-hun rose highest to head the Koreans into the lead.

The goal was a cruel blow to a Reds side that had dominated, but four minutes later they levelled the scores.

Ponte's free-kick, awarded after Washington had been upended, found Abe on the left side of the penalty area and his header across goal was steered home by Hasebe to send the Urawa fans into raptures.

With time running out, Urawa continued to look the more likely to score again with Washington, Ponte and Keita Suzuki all missing the target before the whistle sounded to take the game into extra-time.

Washington came closest to deciding the game in the additional period when he headed Ponte's cross over the target with just six minutes remaining.