Roberto Martínez described Everton's 4-0 defeat in the 226th Merseyside derby as an "embarrassment" as pressure mounted on his position following a shambolic display at Liverpool.

Jürgen Klopp's first experience of the fixture ended in an emphatic win as Divock Origi, Mamadou Sakho, Daniel Sturridge and Philippe Coutinho scored against an Everton side reduced to 10 men following Ramiro Funes Mori's dismissal early in the second half. The Argentina defender received a straight red card for an appalling challenge on Origi, who was taken from the pitch on a stretcher, but Klopp later confirmed the striker's ankle was not broken.

Liverpool will await scan results to determine whether the in-form Belgium man has sustained ankle-ligament damage that could sideline him from the Europa League semi-final first leg against Villarreal next week.

Everton have an FA Cup semi-final at Wembley on Saturday – their opponents, Manchester United, were the only semi-finalists to win a Premier League gameon Wednesday – and apart from being without the suspended Funes Mori, may also miss the ill John Stones and the injured trio of Phil Jagielka, Gareth Barry and Seamus Coleman. The problems mounted for Martínez with Jon Woods, Everton's deputy vice-chairman, leaving his seat in the Anfield directors' box after Sturridge had scored Liverpool's third on the hour.

“It was a pretty shocking night,” said the Everton manager who admitted he was left with “a feeling of embarrassment”. He said: “It was a horrible experience for everyone at Everton Football Club. It was a game that probably turned with the two actions that we didn’t defend well enough in the period of three minutes before half-time. We lost concentration.

“For the first 40 minutes we had a different focus and way about us. Then in that period we gave a soft cushion of two goals which became a massive blow. We tried to regroup and the first action of the second half is a red card incident, then the game becomes a non-event, especially with the big game we have around the corner. From that point on, everything that could go wrong did go wrong.

“Gareth Barry has injured his groin. He is very doubtful for Saturday. He felt it very close to half-time. Maybe he came off at the right time. To lose Gareth Barry through injury, then have John Stones the victim of illness with stomach cramps, and already have Jagielka injured at centre-back, we ended up with two midfielders playing in those positions. We need to forget this showing as quickly as we can.”

Klopp said Origi’s injury had placed a “big shadow” over an otherwise commanding night for Liverpool. He said: “Usually if you tell me before the game that we will win 4-0, I would think I would feel different. Now we have to wait for a final assessment. It is too early now.

“When I came in, everyone who had seen the pictures was worried it was broken, but it is not. I went to see Divock in the medical room. I saw him smiling. The ankle is twisted, and we have to wait to see what has happened to the ligaments. That’s how it is.”

The Liverpool manager described the second half as having “no real fight any more”, a damning assessment of Everton’s display. He said: “Second half, what can I say? It changed completely with the red card, and of course when Stones had to come off it was then really not easy for Everton. We had a good moment, we created chances, we could have scored much more. To be honest, I could sit here and say it was really difficult but in the second half it wasn’t. It was really difficult for Everton; injuries, red card, good opponent. We did well.”

The result – Everton’s second 4-0 loss at Anfield under Martínez in three seasons – the performance and Woods’ abrupt exit intensifies the pressure on their manager ahead of the semi-final with United. Asked whether his position is now weaker than ever, Martínez responded: “That’s not my focus. My focus is to make sure we prepare the game properly for Saturday. It was a really difficult experience for the directors, players and everyone in the stands, especially the fans. There’s no denying that the only thing that matters is to prepare the game on Saturday, regroup and make sure we have that opportunity to repay what the fans deserve.”

(Guardian service)