With just two minutes to go in the final's second leg, played at Saitama Stadium, Silva notched the only goal in the game with a shot from close range, reports Efe.
But Silva clinched the deal when he charged forward on a late attack and blasted the ball past goalkeeper Abdullah Almuaiouf, handing Urawa the title for the second time and giving Japan its first Asian champion since Gamba Osaka in 2008.
Nawaf Al Abed started for Al Hilal in place of Carlos Eduardo, who suffered a serious knee injury in the first leg. "We fed off the crowd's energy and were running on 100 percent adrenalin", added the 25-year-old, who was the target of racial abuse in the build-up to the game. "Without them we wouldn't have been able to win tonight, so I'm really grateful to them".
After a 1-1 draw in the first leg in Riyadh last week, Al Hilal needed to score to have any chance of claiming the club's first Asian title since 2000, but the night was to end in frustration for the Saudi giants.
Al Hilal's task was made harder in the 78th minute when Al Dawsari was sent off for picking up a second yellow card.
"We'll take a little time to recover from tonight and then we go again".
In the first leg played on November 18, Urawa had drawn 1-1 against Al-Hilal, when Silva also gave his team the lead before Syrian forward Omar Kharbin drew level.
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But the visitors eventually settled into a smooth passing rhythm, dictating the pace for the rest of the first half and nearly breaking the deadlock when Uruguayan Nicolas Milesi found himself clear on goal in the 42nd minute.
But twice champions Al Hilal grew more assertive, with Salem Al Dawsari firing narrowly over the bar from outside the area while Nicolas Milesi should have done better before the break when he pulled his shot wide of Shusaku Nishikawa's goal.
At the other end, Reds striker Shinzo Koroki had a header brilliantly saved before Silva almost broke the net with his late rocket to dash Saudi hopes.
And Silva won it for Reds with two minutes left, peeling away from marker Osama Hawsawi to smash Yuki Muto's through ball into the roof of the net and trigger delirious scenes among home fans.
'It was a good participation for us and I'm very proud of all we have done.
"We have done really well in this competition".