Over-training cost Lions series win over All Blacks - O'Brien

Rugby Union - British & Irish Lions Training & Press Conference - Carton House, Co. Kildare, Ireland - 22/5/17 British & Irish Lions Sean O'Brien during training Reuters / Clodagh Kilcoyne Livepic

(Reuters) - Over-training before the first and the final tests against the All Blacks cost the British and Irish Lions the chance to win the three-test series in New Zealand earlier this year, Ireland flanker Sean O'Brien has said.

After losing the first test 30-15 in Auckland, the Lions inflicted a rare home defeat on New Zealand to level the series in Wellington a week later, before a 15-15 stalemate in the third test on their return to Eden Park.