Norwich boss Chris Hughton is prepared for Hull to boast impressive firepower in Saturday's clash at Carrow Road.
Hughton could do with such proven goalscorers himself with the Canaries on an eight-match winless streak during which they have scored just four goals.
Hull beat Norwich 1-0 on their own turf, and Hughton said of Jelavic and Long: "Of course they are two quality players and that's the reason why I presume they wanted to bring them in. Certainly they have brought in two good players.
"What we've been missing is the quality at both ends but especially scoring the chances to win games.
"We know that we're on a disappointing run, and the best way to solve that one is by showing the grit and determination to win games."
Hull are in 10th place in the Premier League table, five spots ahead of Norwich, but Hughton pointed out only three points separate the sides.
He added: "It shows how tight it is in this division. But you can't hide facts and the fact is we have not won for eight games including cup games.
"There's no doubt it's a big game. I think the fact that we're playing at home is important and that we're playing a team who are not too far above us in the division who have been deemed to have had a very good season so far.
"It's also a big game for us because we want to improve on our form. We're disappointed with where we are this particular moment."
Hughton may give a debut to new signing Jonas Gutierrez for the visit of Hull.
Argentinian midfielder Gutierrez, who joined from Newcastle, has declared himself fit while Alex Tettey and Anthony Pilkington will also both be in the squad after long injury absences.
"He certainly comes into contention," said Hughton of his new recruit. "He's enthusiastic and was a very well-liked player up at Newcastle by the supporters and can play on either flank or a couple of other positions."
Gutierrez, who expressed his bafflement at being made surplus to requirements at Newcastle, is also backing Norwich to stay up this season.
He said: "The squad has the quality, now we need a few results to get the confidence back. One of the best things in football is to get results soon to have that confidence again."