From Longman Dictionary of Contemporary Englishthird time luckythird time luckyBritish English, (the) third time’s the charm American English spoken used when you have failed to do something twice and hope to be successful the third time → third
Examples from the Corpus
third time lucky• Barcelona, having lost the 1961 and 1986 finals, hope it will be third time lucky.• Everyone is praying that this time it will be third time lucky.• Maybe he's out there thinking: third time lucky.• Odds-on favourite last time at Haydock, he was narrowly beaten into third place, but tomorrow should prove third time lucky. 