Jelavic set up fellow January signing Long last weekend to score the Tigers' goal in their 1-1 draw with Tottenham Hotspur.
Long now hopes that the he and the Croatian can find the net on a regular basis to help push the team up the Premier League table.
"I can sense an understanding there and it's exciting," he told the club's official website.
"Nikica is a very good player and easy to play with. The first thing we think about when we get the ball is where on the pitch the other one is.
"Although it is still early days, I think it can grow into something good."
Hull continue their Premier League campaign on Saturday when they travel to Sunderland.