User blog comment:Crazylittlefreakgirl/Fairy Tail Official Pairings?/@comment-1535822-20130513114732/@comment-7418318-20130526150804

There is the phantom arc, when everyone retreats and Natsu set's out alone (with Happy, but the two are almost one being anyway) to save her and the following jump out of the tower.

Then there is the Rainbow Sakura Scene, or when the raft scene in the Oracion Seis arc, the scenes between Natsu and Lucy after Naval battle and Natsu's insistance on being in the rescue team and many more scenes beside all those.

As those examples show, there is FAR more than just this one fanservice chapter. Chapter 331 just reinforced what was already very strongly established.