Andre Carrillo scored the winning goal as Al-Hilal beat Urawa Red Diamonds 1-0 in the AFC Champions League final first leg.
A goalkeeping error from Haruki Fukushima allowed former Watford winger Carrillo to steal in and score, putting Razvan Lucescu's side on course to avenge their defeat to the same opponents in the 2017 final.
The Saudi Pro League leaders went into the game on the back of an indifferent run of form, having won just one of their previous four in all competitions, and Lucescu will have been pleased with the way his players hogged possession but less so by their wasteful finishing.
Urawa are now winless in four games in all competitions and failed to make an impact on Saturday, but the narrow aggregate scoreline will give coach Tsuyoshi Otsuki hope of a second-leg turnaround in Saitama.
Al-Hilal attacker Sebastian Giovinco blazed the hosts' first clear chance over after 14 frenetic minutes at a packed King Saud University Stadium.
Bafetimbi Gomis headed high as the home side ramped up the first-half pressure, but the determined Reds held firm and the game was deadlocked at the interval.
Urawa sat back again in the second half as they aimed to absorb waves of Al-Hilal pressure, but Fukushima's failure to claim Mohammed Al-Burayk's pass after an hour gave Carrillo the chance to head a simple finish into an empty net.
Lucescu's men went in search of a scoreline their performance deserved but Salem Al Dawsari had a goal wrongly ruled out for offside as their incessant pressure failed to tell.
Giovinco was denied by a good Fukushima save and he fired another shot wide nine minutes from time, leaving Al-Hilal frustrated despite claiming victory at the final whistle.