(Adds club statement on disorder)
Nov 29 (Reuters) - Celtic's slump continued when they were dumped out of the Scottish League Cup by Ross County on Sunday as manager Neil Lennon admitted it was time for some soul searching.
The 2-0 second-round home loss, Celtic's first in a domestic cup since losing to city rivals Rangers in the 2016 Scottish Cup semi-finals, ended their vice-like grip on the silverware.
Under Lennon and his predecessor Brendan Rodgers, Celtic have won everything on offer in Scottish football since 2017 but the wheels appear to be falling off.
They are 11 points behind Rangers in the Scottish Premier League, albeit with two games in hand, and in midweek were thrashed 4-1 at home by Sparta Prague in the Europa League in which they are bottom of their group and unable to progress.
It was Ross County's first win at Celtic Park and probably the only saving grace for Lennon and his players was that there were no fans present to vent their anger.
Hundreds gathered outside the stadium to voice their disapproval, disobeying strict lockdown rules, and there were ugly scenes as some clashed with police and security staff.
"While we sincerely share the huge disappointment of all Celtic supporters, there can be no excuse for some of the violent scenes at Celtic Park this evening," a statement said.
"Our players and a management team, who have given so much in recent years and have delivered 11 consecutive trophies, to require an escort from Celtic Park while being targeted with missiles, is simply unacceptable."
Lennon acknowledged that the pressure was intensifying after only two wins in their last 10 matches in all competitions.
Celtic have suffered four successive home defeats for the first time since January 1958.
"There is an expectation at this club, there's a demand for excellence and there's a demand for wins -- I am fully aware of that," said Lennon, who began his second spell in charge of Celtic in February 2019 after Rodgers left for Leicester city.
"I am not standing here like the happy clapper saying everything's okay, because it's not.
"But we'll do everything we can -- if I've still got the opportunity to do that -- to turn things around."
County's victory was sealed via Ross Stewart's first-half penalty and Alex Iacovitti's late header as they reached the quarter-finals where they visit Livingston.
While they celebrated, Lennon admitted it was a "bad moment" ahead of Thursday's Europa League trip to Italian giants AC Milan in which they are merely playing for pride.
"Sometimes, on a run like this, your legs feel a bit heavier, your thinking is not too clear," he said.
"There's a lot of soul-searching for me and my staff. I don't want to put too much on the players because they are devastated in there." (Reporting by Martyn Herman; editing by Clare Fallon, Ken Ferris and Sam Holmes)