The Egyptian army claims that it killed Abu Duaa al-Ansari, leader of Daesh's branch in Sinai, last Thursday.
The air strike near El Arish, in which the Egyptians say that 45 Daesh fighters were killed, was another blow to the terror group's affiliate on Israel's border, which has been on the back foot in recent months.
The unconfirmed attack was part of a series of successful strikes by the Egyptian air force against the Salafist group, originally named Ansar Bait al-Makdas, which pledged allegiance to Daesh's caliphate in 2014.
The Egyptian pushback comes after a series of successes by the Sinai terror outfit in ambushing security forces in the peninsula and blowing up a Russian airliner that took off from Sharm el-Sheikh Airport.
Before last week's attack, Israeli intelligence was already of the view that the Egyptian forces had significantly degraded Daesh's capabilities in Sinai and that the number of fighters available to the group had decreased from around 1,000 to about 300.
Israel believes Sinai Daesh has been degraded
The Egyptian strike came shortly after Daesh in Sinai uploaded a video warning that it would take revenge on Israel over its support for the Egyptians. "Your account with us has become heavy and you will soon pay a high price," the movement stated in the video. They have yet to launch an attack on Israel, probably because it is much better defended against terrorism than Daesh's other targets.
Israeli intelligence officers have said in recent months that they believe it is a matter of time before Daesh tries to attack Israel from Sinai or the Golan.
While Israel does not openly refer to its participation in operations against Daesh, there have been reports of close co-operation with the Egyptian army.
Aircraft from the Royal Air Force, as well as other Western countries fighting Daesh, are regularly sighted crossing Israel's airspace, on the way and returning from bombing Daesh targets in Syria and Iraq.