The Welsh region controlled the game for long periods, frustrating their hosts as they got their European campaign off to the best of starts.
It took Cardiff a while to recover from the shock of James Down’s leg injury, with the second row stretchered from the field in the opening minutes and the Blues found themselves 6-0 down to a penalty by full back Gaeten Germain and a drop goal by fly-half Juan Martin Hernandez.
But when the visitors did strike, it led to the game’s first try. Paul Tito was tackled into touch just short of the Racing line after a slick handling move but from the lineout, Tongan prop Tau Filise picked up the loose ball for an easy try.
Fly half Dan Parks added the conversion to put the visitors a point ahead before the Scot and Germain swapped penalties to give the Cardiff Blues a 10-7 lead midway through the first half.
Racing Metro restored their lead with Argentine Juan Imhoff touching down but just before the break the Blues grabbed their second try with rookie wing Alex Cuthbert scoring in the corner to give the Blues a 17-14 half-time lead.
Parks and Germain swapped penalties during the second period, Parks kicking three to Germain’s two as the Welsh region hung on for a deserved victory.
