Tottenham midfielder Moussa Sissoko (left) started in Gent on Thursday
Tottenham lost 1-0 in Belgium, with Sissoko part of a strong XI named by manager Mauricio Pochettino.
But the Premier League side were out-fought on the night and must now reverse the tie next week back in London.
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Tottenham Hotspur are in the process of building a new 61,000 capacity stadium on the site of White Hart Lane, due to open at the start of the 2018/19 season
You would hope he has more to show
Allen on Sissoko
And Allen singled out Sissoko for criticism, claiming the £30million summer signing from Newcastle has not proven himself.
“The first-half performance was very poor,” Allen said on talkSPORT.
“He played in front of Kyle Walker and it restricted (Walker) going forward.
“They put him out on the left wing in the second half. It released Walker on the right playing three at the back and all of a sudden Spurs had a decent spell.
“You would hope (Sissoko) has more to show because it’s difficult to see him holding his place in the team at the moment.”
Clive Allen believes Sissoko must show more at Spurs
Tottenham lost 1-0 in Belgium
Sissoko could start for Tottenham against Fulham on Sunday in the FA Cup fifth round.
He is yet to score for the north London club since he arrived from Championship side Newcastle.