Tomer Header converted from six yards out for the game's only goal between last season's Championship top two, seeing his side prevail 1-0 on the south coast.
Benitez feels that there was an infringement inside the box from the free kick which Hemed converted from, however, while also bemoaning the Magpies' failure to put the ball in the net at the other end.
"We did enough to get a point at least," he told Sky Sports News. "Both teams had chances. We had a lot of control and good chances at the end. The goal for me was a foul, pushing and blocking. But you cannot change the decision.
"We deserved more. We are still without too much experience in the Premier League. We have to manage these situations a bit better."
Benitez has now lost each of his last four Premier League matches against newly-promoted sides, following a run of just two in the first 40.