A potentially serious injury to in-form striker Divock Origi cast a shadow over Liverpool's 4-0 thumping of Everton in the 226th Merseyside derby.
The usually ebullient Jurgen Klopp admitted he found it difficult to raise a smile despite Origi, Mamadou Sakho, Daniel Sturridge and Philippe Coutinho completing a rousing victory over their near-neighbors.
Origi, who has become Klopp's first-choice after scoring five goals in as many matches, was carried off on a stretcher after Ramiro Funes Mori was sent off for stamping on his ankle.
"Everything is okay – apart from Divock," said the Liverpool manager.
"Usually after 4-0 I don't know how to keep my smile off my face but it is pretty easy.
"If you told me before the game we would win 4-0 I thought I'd feel different.
"It is a big shadow on the game to be honest.
"Everyone who saw the pictures said maybe it is broken – it is not. We have to wait for a final assessment, it is too early.
"I went to Divock in the medical room and I saw him smiling.
"The ankle is twisted and we have to wait to see what has happened to the ligaments."
The visitors were 2-0 down at half-time but once Funes Mori departed and then fellow centre-back John Stones went off ill they simply capitulated.
Even Klopp appeared to feel some sympathy for their beleaguered visitors, who now have to lift themselves for Saturday's FA Cup semi-final against Manchester United – a match which counterpart Roberto Martinez may well have to win to save his job.
"To be honest I could say it was really difficult but the second half wasn't," Klopp added.
"It was really difficult for Everton; red card, injuries, good opponent.
"The second half changed completely with the red card and then the next change when Stones had to come off that was really not easy for Everton.
"There was no real fight any more. That is not usual. There have been a lot more intensive derbies for sure and there will be a lot more intensive derbies."