Andrew Trimble has demanded an emphatic response to Ireland's nightmare summer tour when they face South Africa.

Ireland open the autumn Test Guinness Series at Lansdowne Road on Saturday hoping to halt a run of four successive defeats dating back to England in the RBS 6 Nations.

Their darkest hour arrived against Zealand in the third of June's three-Test series when they were thrashed 60-0 in Hamilton.

"It was a massive disappointment after the tour. It's not a tour that any one of us is proud to have been on," Trimble said.

"There's frustration at getting beaten so badly. It's a long time waiting to put things right.

"It's not a performance we're proud of and it's something we want to put right. It can go one of two ways.

"You can dwell on it and divert down a bad path or you can bounce back from it. Hopefully we can bounce back."

Trimble accepts that Ireland's patchy form, which can range from the sublime to the ridiculous in the space of a week, is a mystery even to themselves.

"We've been up and down over the last few years. The inconsistency showed in the second and third Tests," he said.

"I don't know if we are the team that performed in the second Test or the team that performed in the third Test, but we've shown that we're capable of producing either performance.

"We were very close to beating the All Blacks in the second Test.

"It would be weak minded if we looked back and said we're just not that good.

"Looking at it logically we've produced big performances over the last few years and we know that if we do that we'll get big results."

Both Ireland and South Africa have been hit by the loss of key personnel to injury in the build up to Saturday, but the home side were at least given some promising news yesterday.

Assistant coach Mark Tainton revealed that Paul O'Connell and prop Cian Healy are on course to play after winning their battles with respective back and shoulder injuries.

With established internationals Brian O'Driscoll, Sean O'Brien, Stephen Ferris, Rob Kearney and Rory Best already ruled out, Ireland could ill-afford any further losses.