Salem Al-Dawsari scored two penalties as Al Hilal beat Flamengo 3-2 on Tuesday to reach this weekend's Club World Cup final in Morocco.
The Saudis on Saturday will play the winner of Wednesday's other semi-final between European champions Real Madrid and Egypt's Al Ahly.
Al-Dawsari's first spot-kick came in the fourth minute after Luciano Vietto was felled by Flamengo right-back Matheuzinho.
The Saudi Arabia forward became the first player to score against the same opponents in two editions of the Club World Cup after also netting against the Brazilians in 2019.
The teams were level a quarter of an hour later as striker Pedro side-footed his effort first time past 36-year-old Abdullah Al Muaiouf.
Al-Dawsari's second penalty came nine minutes into first-half injury time after Vietto was tripped by former Marseille midfielder Gerson.
Gerson was sent off for a second yellow card, having received his first on 15 minutes for diving in the Al Hilal box.
With 20 minutes remaining, Al Hilal moved closer to the final when Argentinian Vietto fired in off the crossbar after Al-Dawsari's clipped pass.
After 20 seconds of the six minutes of additional time, Pedro cut the deficit with an easy tap-in but it was not enough to spark a late comeback from the Copa Libertadores champions.