Ireland coach Eddie O'Sullivan believed his side 'ran out of gas' as they just failed to overhaul South Africa in the 26-17 second Test defeat in Cape Town.
The result gave the Springboks a 2-0 series victory but O'Sullivan's side had fought back from a 23-7 deficit just before the break to be within one score of the victory but they just could not pull it off.
"To be honest, my guys were running on empty out there,'' said the Ireland coach.
"You could see that we were at the end of a very long season and, although they gave everything, they needed a break and didn't get it.
"I am still very proud of them however.''
Ireland dominated the second half as the young Springbok side wilted in the face of concerted pressure.
The visitors, however, could not turn that possession and pressure into points.
"We had opportunities, but somehow we just did not finish,'' added O'Sullivan.
O'Sullivan's praise of his players' second-half performance was echoed by counterpart Jake White, who also complimented his side on their first half.
"Our guys started this game like they finished the first Test and then went quiet in the second half. It would be a real step forward if we can put two halves together,'' he said.
Irish captain Brian O'Driscoll said the series defeat was a disappointment and took some of the lustre away from a successful season.
But he added: "We did, however, get some monkeys of our backs,
"To win the Triple Crown obviously and go to Twickenham to do it was huge; also to hang on against Scotland when in the past we might have let that slip.''