Faf du Plessis admitted South Africa's limp World Cup exit was embarrassing as the furious captain branded his under-performing team “mediocre” and challenged them to take responsibility for their disastrous showing.

The Proteas cannot qualify for the semi-finals after slumping to a 49-run defeat against fellow strugglers Pakistan at Lord's on Sunday.

With two games to play, South Africa have failed to make the knockout stages for only the second time.

The tame manner of their elimination was tough for Du Plessis to swallow as he watched his side struggle to 259-9 in response to Pakistan's 308-7.

“The results we are dishing out at the moment, it's tough. The way we played today is borderline embarrassing,” Du Plessis said.

“It started with our bowling. There were a lot of bad balls on a wicket where if you just bowled line and length it was going to be hard for them.

“It was a five out of 10 performance with the ball, then the same batting. We started nicely, got a partnership going, then wickets fall.

“We are a mediocre team at the moment because we are making the same mistakes. One step forward and two steps back is not a good team.”

Du Plessis said his players were suffering from a chronic lack of confidence.

The skipper top-scored for his team on Sunday with 63, but received little support as the Proteas played too cautiously, then threw their wickets away in a desperate bid to get back into the match.

“The guys are playing with low confidence and making the same mistakes. It just rolls on, it's such a snowball effect,” he said.

“The real, honest answer is it chips away at you. You try really hard, then come back the next game and make the same mistakes. It chips away at your confidence and your ego as a player.”

Frustrated that South Africa, defeated in five of their seven World Cup matches, have only beaten minnows Afghanistan in the tournament, Du Plessis demanded his players show more desire to sort out their problems.

“As much as I can say, or the coach can say, the responsibility lies with the player to sort it out yourself if you are low on confidence,” he said.

“Everyone has played the game long enough to understand you go through highs and lows.”

'Humiliating'

Du Plessis said the humiliating exit was the lowest point of his career, adding: “I'm a very proud player and captain. Playing for South Africa means a lot to me.

“There are people rightly and fairly criticising the team because we are not playing the cricket we should.

“It's important myself, the coach and the senior players front up to this challenge.”

Du Plessis also blamed burnout for their woes after several South Africa players, including the skipper, played in this year's Indian Premier League.

“It's important we find space to rest our three-format players. They are playing a lot of cricket. That's the one area I would have changed but it's not in my hands,” he said.

Du Plessis said he would not walk away from the job.

“I've always said the most enjoyment I get from the game is captaining the side. The fact we are playing way below our potential is not something that sits well with me,” he said.

“I'm trying as hard as I can, but unfortunately not everything is down to me. My character is I will try to fix as many problems as I can.”