The phrase "flawless performance" means that someone or something achieved an outstanding or perfect performance without any mistakes or errors. Full definition
It's pricier than the last generations, but an amazing camera and near - flawless performance make this the most complete - feeling Moto G yet. (smartphone.ninja)
Proficient in handling any acting part with variation and give flawless performance. (sampleresumeobjectives.org)
Of particular highlight is the performance of Microsoft» Windows Defender Antivirus, which scored no less than 17 points in the research, with flawless performance in the protection tests. (news.softpedia.com)