Chelsea head coach Enzo Maresca said the sacking of Erik ten Hag has forced him to re-think preparations for Sunday's trip to Manchester United.
The game at Old Trafford will be United's first in the Premier League since a poor start to the season prompted them to dismiss their manager of nearly two-and-a-half years, with assistant Ruud van Nistelrooy placed in interim charge.
Sporting CP manager Ruben Amorim has been heavily linked with the role, but should an appointment not have been made by the weekend it will mean a reunion in the dugout for Maresca and former United striker Van Nistelrooy, who played together for a year at Malaga between 2011 and 2012.
It has also meant extra homework for the Blues boss, who has had to dig out videos of the stand-in manager's former club PSV Eindhoven.
"I guess it will be Ruud (in charge)," said Maresca. "He's a friend of mine, we played together, we spent a year together at Malaga and we still have a relationship.
"We started to watch some PSV games. We'd already watched many Man United games. I'm sad for Erik and in the same time happy for Ruud. Hopefully I can see him Sunday."
Before that Chelsea face a trip to face Newcastle at St James's Park in the fourth round of the Carabao Cup on Wednesday.
Last season, the team then managed by Mauricio Pochettino reached the final of the competition but were thwarted by Liverpool in their bid to land a first major domestic trophy since 2018.
The 1-0 extra-time defeat at Wembley to a Reds side decimated by injury to senior players drew much criticism, with Sky Sports pundit Gary Neville famously calling Pochettino's expensively assembled team "billion pound bottle-jobs."
Chelsea's average age that day was actually around two years younger than Jurgen Klopp's side, with Liverpool boasting a wealth of experience in their starting XI.
"I didn't hear (Neville's) comment," said Maresca. "But I still remember watching TV and they showed the number of finals Liverpool's players had played and the number of finals Chelsea's players had played. The difference was huge. That shows the difference between the two clubs at the moment.
"The reason I say in this moment we are not close (to Liverpool) is because you need to live moments, you need that experience to improve things."
There are likely to be wholesale changes to the XI that beat Newcastle in the league on Sunday, with Eddie Howe's side set to come up against Maresca's second string.
That means a start in goal for understudy Filip Jorgensen, but despite the summer signing having impressed in the cup competitions the head coach said there is no prospect of him displacing number one Robert Sanchez.
"At the moment the number one is Robert," said Maresca. "In football things can change game after game, but if you ask me now the number one is Robert. There is no doubt."
