If Northern Ireland manager Ian Baraclough is hoping to avoid any refereeing controversy tonight then he is well advised not to ask Pep Guardiola for his views on Antonio Mateu Lahoz.
The Spanish official, who will be in charge of the Euro 2020 play-off semi-final at the Grbavica Stadium, dropped off the Manchester City manager's Christmas card list in 2018.
Guardiola's frustration with 43-year-old Mateu Lahoz boiled over after City were dumped out of the Champions League at the quarter-final stage by Liverpool.
The City chief accused the official of being "a special guy" who "likes to be different" after Liverpool sealed a 2-1 second-leg win at the Etihad and a 5-1 aggregate triumph in the last-eight tie and was fuming after a Leroy Sane goal had been ruled out for offside.
A furious Guardiola confronted Mateu Lahoz at half-time and was sent to the stands.
Hopefully it won't be the same tale of woe for Baraclough, and the Northern Ireland players and fans have every right to be on edge after what happened in their last play-off battles.
Michael O'Neill's side never recovered from a controversial penalty awarded to Switzerland in November 2017 at Windsor Park as they fought to make their first World Cup since 1986.
In the first leg, Ricardo Rodriguez scored with a penalty just before the hour mark after Corry Evans was deemed to have handled inside the area and that goal was decisive.
Romanian referee Ovidiu Hategan admitted later he got the call wrong and he was left off Fifa's final list of 36 referees and 63 assistants for Russia.