Tottenham need a "lightning quick" attacker to complement Harry Kane up front, according to Tony Cascarino.
Spurs came up short against a streetwise Monaco side at Wembley on Wednesday night as individual errors cost Mauricio Pochettino's side dearly.
Toby Alderweireld's header threatened to turn the tide on the stroke of half time but the north Londoners produced a collectively blunt performance in attack to disappoint the 85,000 fans in attendance.
Kane was guilty of missing a gilt-edge opportunity and struggled to get into the game, with Cascarino adamant Spurs failed to exploit the extra space on offer at England's national stadium.
"Spurs lack someone who is lightning quick in attack," Cascarino told the Times.
"I wouldn't want to take anything away from Harry Kane, who had a marvellous season last term, but having the option of a bit more pace in attack would make them a better team.
"The fact that Wembley has a larger playing surface than White Hart Lane should have suited Tottenham down to the ground because the team are packed with youth and energy.
"But they didn't use that space very well," he added.
Pochettino introduced Vincent Janssen and Moussa Sissoko in an effort to get Spurs back into the game but neither man could find a way through Monaco's stoic defence.
Spurs sit bottom of Group E after matchday one and Pochettino has urged his side to learn their lessons quickly ahead of a trip to face CSKA Moscow on September 27.
