What now for O'Neill and Celtic?

Celtic lost 1-0 to Rangers with their lead at top of Scottish Premiership cut to two points; it was their second Old Firm defeat inside a week; Martin O'Neill's side have suffered three straight defeats

There is no denying Martin O'Neill is a legend at Celtic, but is a change needed before their problems become a crisis?

The 74-year-old has already said he will stock and decide if it is "time to wrap it up" following the 1-0 loss to Rangers at Parkhead.

That defeat was their second against the Old Firm rivals inside a week that also saw them go down 3-1 to Ferencvaros in the Europa League.

Each display has been as concerning as the last, with the Hoops fans worried about what the rest of the season holds if nothing changes during the international break.

Celtic started the latest defence of their Scottish Premiership title with six straight wins, but at times they were unconvincing.

Their epic collapse in their Champions League play-off against LASK - from 4-0 up to crashing out 5-4 on aggregate - raised questions about O'Neill and his players.

A pasting last weekend against Rangers in the Scottish League Cup, followed by another abject display in the Europa League, saw the pressure increase.

Then came a 1-0 loss to their Old Firm rivals in front of 60,000 of their own fans.

They are still top of the top flight heading into a three-week international break, but it is a two-point gap rather than the commanding eight-point lead they could have had.

It is easy to point the finger at the manager when the results do not come, but Celtic's problems are bigger than that.

There were fan protests against the club's board last season and calls for change at the top have not gone away.

Questions have been asked about the quality and timing of the summer signings.

While record signing Kasper Hogh and Camilo Duran were brought in before their Champions League exit, the club then spent almost £20 on Mika Baur, Haissem Hassan and Joel van den Berg before Deadline Day.