Spurs will travel to Larnaca in Cyprus and it could be a tricky game for Mauricio Pochettino’s side, with AEL having already defeated Zenit St Petersburg 1-0 there this season in a Champions League qualifier.
They were defeated 3-0 in the return leg in Russia but Petev says that result has given his team confidence and insisted they were capable of upsetting Spurs if they limit their mistakes.
"I believe 21 August will be a very good day for AEL," Petev told the UEFA website. "There is belief and it is vital that there is in the squad.
"We managed to beat a club like Zenit in our previous tie in Europe and were then unlucky to go out against them because we played with 10 men for some 70 minutes (in the second leg). But that is now behind us.
"They are a massive club and it is crucial we minimise our mistakes against them because they know how to punish every little error.
"The truth is that this was a very difficult draw for us and we were not so lucky. But, that aside, it is very important that we are ready for the first game and play well."
Captain Marios Nikolaou acknowledged his team face a tough test against the Premier League big-spenders but revealed he and his team-mates were relishing the opportunity.
"This game will be an experience for us all and a challenge," said the midfielder. "We know they are a great side but we certainly don't fear them – we will look them in the eye.
“We will need to be at our best. We were handed a tough draw, but that is football and we need to be ready."