Shizuoka - A furious Italy coach Conor O'Shea on Friday lambasted prop Andrea Lovotti for "crass stupidity" after his dangerous dump tackle on Duane Vermeulen left the remaining 14 men with an "impossible" task.

Italy had come out strongly in the second half of their Rugby World Cup encounter against South Africa and were threatening the Springbok line at 17-3 down.

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But Lovotti, aided by Nicola Quaglio, picked Vermeulen up by his feet and speared him head-first into the turf, leaving referee Wayne Barnes with little option but to give a straight red card.

"At 17-3, we had to hang in and do something and we get to the start of the second half, we're close to the line and then just crass stupidity, crass stupidity," fumed O'Shea.

"I'm destroyed really for everybody because we worked so hard," added the coach, whose team must now beat defending champions New Zealand to have any hope of reaching the quarter-finals.

"I thought the boys fought valiantly but when you're down in numbers against a great side, it's just impossible," he said.

Italy will have to face New Zealand with a lengthy injury list after losing prop Simone Ferrari in the first minute and then his replacement Marco Riccioni, meaning scrums were uncontested.

Lovotti will almost certainly be suspended for the All Black encounter, deepening O'Shea's woes in the front row.

"We'll see what's the best 23 we can get fit and on the pitch for next week," said O'Shea, as his men face the All Blacks on October 12 in Toyota.

"But we're hurting massively because we came here to really show our best and we didn't get that opportunity in the second half. Seventeen-three, you lose that man and the game is done."

South Africa coach Rassie Erasmus also highlighted the red card as the turning point.

Describing the fixture as a "slippery" potential banana-skin, Erasmus said he felt Italy were getting back into the game when Lovotti was sent off.

"When they got that red card, it was quite easy for us after that," said Erasmus, whose team plays Canada on Tuesday.