Three-time European champions Inter Milan were humbled at home by Hapoel Be'er Sheva in a 2-0 defeat in their Europa League opener on Thursday.
The Israeli side previously gave Celtic a scare in their Champions League playoff before the Scots scraped through 5-4 on aggregate last month, but they overwhelmed Milan to increase the pressure on manager Frank de Boer.
Defender Miguel Vitor couldn't have chosen a better time to score his first goal for Be'er Sheva, tapping in from close range to give the visitors the lead in the 54th minute.
Maor Buzaglo doubled the lead 15 minutes later, curling in a free kick.
Ben Bitton almost made it 3-0 shortly before full time but hit the crossbar.