Jonathan has voiced his frustration with Inter's inability to convert chances in the aftermath of their 0-0 draw against Catania in Serie A.
The Giuseppe Meazza side have been struggling to find their best form in the past few weeks and still await their first victory of 2014.
Additionally, Inter have scored only once in their last five official matches and Jonathan feels they have been very unfortunate up front.
"We’re lacking a bit of luck because we’re trying to score in every possible way, sending in balls up front ..." Jonathan told the official Inter website.
"We’re not managing to convert our chances. That’s all we’re lacking. Once that starts happening again we’ll be able to move forward. I’m certain of that.
"When a defensive team finds itself down a goal it has to open up the play and then the game changes."
Inter remain fifth in the Serie A table, but Torino, Parma and Verona are within one point of the Nerazzurri.