French-born Malta international Teddy Teuma gave the Belgians the lead just before the half-hour mark, and Union Saint-Gilloise scored a potentially crucial second goal in controversial fashion 14 minutes from time.
Connor Goldson was penalized for a handball in the area following a VAR review and Dante Vanzeir stepped in to score the resulting penalty.
Related News
Watch: England players gatecrash press conference singing ‘It’s Coming Home’ after Women’s Euro win
Neymar, Messi and Ramos lift Champions Trophy for PSG in new coach Christopher Galtier’s debut
Unable to host Rangers at their own stadium, the game was played in nearby Leuven, but that was no liability for the Union.
Giovanni van Bronckhorst’s Rangers will face a tough fight in the second leg next Tuesday, August 9.
Related News
Darwin Nunez overtakes Erling Haaland as Liverpool beat Man City 3-1 to win Community Shield
India, hosts of the FIFA U-17 Women’s World Cup 2022, will get our girls excited about sport: PM Narendra Modi
“It’s very disappointing, especially when our performances weren’t at the level where we normally are and at the level you need to compete at that level,” Van Bronckhorst told the BBC.
On the penalty, he added: “You are playing in the biggest competition in Europe, with so much at stake, and giving away a penalty like this is very difficult.”
Beaten Europa League finalists last season, Rangers are looking to return to the Champions League group stage for the first time in over a decade.
The winners of the third qualifying round will take part in a play-off later this month against Monaco or PSV Eindhoven, with the winners progressing to the group stage.
Monaco needed a late equalizer from centre-back Axel Disasi to draw 1-1 with Ruud van Nistelrooy’s PSV at the Stade Louis II on Tuesday.
Disasi headed home from close range when an Ismail Jakobs free-kick landed on him in the penalty area 10 minutes from time.
Monaco missed out on direct qualification for the group stage by conceding a goal in stoppage time on the final day of the Ligue 1 final season and thus fell from second to third place in the standings, behind Marseille.
Enzo Fernandez also scored for the Portuguese side with Pione Sisto getting a late consolation from the penalty spot.
Previously, Viktoria Plzen of the Czech Republic and Dinamo Zagreb of Croatia won 2-1 away against Sheriff Tiraspol of Moldova and Ludogorets of Bulgaria respectively.
