Helton believes the Gunners have become ‘weaker’ in recent years.
Helton said: “We’ve been watching Arsenal’s last few games closely and they’re not as strong as they’ve been in recent years. That can be to our advantage.
“The tie is very balanced. We certainly don’t see Arsenal as the favourites.
“We’ve not had much luck against the English clubs in the last few seasons.
“Now is the moment for to break that run of set-backs and reach the Champions League quarter-finals.”
Helton added: “We’ll settle with a 1-0 victory in the home leg because we truly believe we will score in The Emirates Stadium when we visit London.
“Without Emmanuel Adebayor and the injured Robin Van Persie in attack, Arsenal are not as explosive in attack.
“Arsenal have a good squad but I believe that we will defeat them this season.”