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In late January, Union Saint - Gilloise faced a disappointing defeat. Despite having several opportunities to draw the game in the closing stages, they ultimately lost 2 - 1 to Rangers at Ibrox in their final league - phase fixture.

In the early part of the league campaign, the Belgian club faced difficulties. Losing and drawing two of their first four matches, they were clearly underdogs in the race to reach the last 16 by finishing in the top eight. As a result, they were relatively satisfied with securing a playoff spot.

This loss to Rangers was an increasingly uncommon setback for Sebastien Pocognoli's team. Since then, they have shown great resilience, winning consecutive league games and continuing an impressive run of form.

After recent triumphs over Sint - Truidense and Kortrijk, Union Saint - Gilloise have had a remarkable run in all competitions. In their last 20 matches, they have won 13, drawn five, and lost only two.

Thanks to this outstanding performance, they have climbed up to third in the Pro League standings. Union Saint - Gilloise are once again exceeding expectations compared to their rather unremarkable recent history. The club last achieved significant success in the 1960s, but now they are emerging as a rising power in Belgian football.

Europa League quarter-finalists in 2023, Les Unionistes must now try to win the first leg of a UEFA knockout tie for the first time in 66 years, having gone 10 without a win since then.

Meanwhile, more recently, Ajax have won just one of their last 10 knockout games in Europe - somewhat fortunately beating Bodo/Glimt in last season's Conference League.

The Amsterdam club are undefeated in their last five trips to neighbouring Belgium, though, and they can count on the backing of 2,300 travelling fans.

Virtually assured of a playoff spot ahead of the final matchday, Francesco Farioli's side finished 12th in the table with a 2-1 home win over previously unbeaten Galatasaray.

That was the third of four straight successes at Johan Cruijff Arena - the most recent coming in Der Klassieker. Getting one over on old foes Feyenoord, Ajax snatched all three points as Kenneth Taylor netted a stoppage-time winner.

Then, they moved top of the Eredivisie for the first time in more than two years by beating Fortuna Sittard, as reigning champions PSV Eindhoven dropped points for the fourth time in five league matches.

After Wout Weghorst belatedly opened the scoring, Christian Rasmussen then slid in a second goal with almost the last kick, leaving them level on points with PSV - and holding one game in hand.

After an eventful cameo against Fortuna Sittard - where he came on after an hour, opened the scoring, then provided an assist - Wout Weghorst will be unavailable on Thursday, as the Ajax frontman also sustained a toe injury and has been ruled out for six weeks.

Having seen Chuba Akpom leave for Lille, Francesco Farioli now has just one senior striker at his disposal, so Brian Brobbey is set to start up front; supporting from out wide, Burkinabe winger Bertrand Traore has five goal involvements from six Europa League appearances this season.

Recent signing Youri Regeer has also been sidelined, soon after being brought in to replace Roma-bound Devyne Rensch, while Owen Wijndal and Mika Godts are still struggling with injuries.

Deadline day arrival Lucas Rosa has been named on the visitors' UEFA list, though, and veteran Jordan Henderson decided to stay for the rest of the season after almost signing for Monaco; key defender Jorrel Hato is back from a domestic suspension.

Meanwhile, Union will be without English centre-back Ross Sykes, who is still suspended after being sent off right at the end of last month's league-phase game against Braga.

Koki Machida has now served his one-match ban and can return to the hosts' lineup, albeit Ousseynou Niang is also in contention to operate along the left flank.

Sofiane Boufal and Alessio Castro-Montes are both doubtful due to injury, but Canadian striker Promise David has been added to USG's knockout-stage squad list; the latter could partner main marksman Franjo Ivanovic.

Union SG possible starting lineup:

Moris; Mac Allister, Burgess, Leysen; Khalaili, Vanhoutte, Van de Perre, Sadiki, Machida; Promise, Ivanovic

Ajax possible starting lineup:

Pasveer; Gaaei, Sutalo, Baas, Hato; Klaassen, Henderson, Taylor; Traore, Brobbey, Berghuis