The Blues had won three of their last four GUINNESS PRO12 games before fronting up to the champions at BT
Sport Cardiff Arms Park - and were motoring along nicely after a Manoa Vosawai try and Gareth Anscombe's kicking haul of eight points.
However, Jarrad Hoeata's red card just before the break - for a swinging arm tackle on Rob Kearney - spoiled their fine start and Leinster came roaring back.
Jimmy Gopperth, Noel Reid, Tadhg Furlong and Luke McGrath all crossed the whitewash as the Irish province won 22-13, leaving the Blues staring up from ninth place in the GUINNESS PRO12 table.
However, back-row Navidi is certain that things will click in the long run - and believes the European break can act as a springboard for success.
"Our ambition is to climb the table as high as we can - that hasn't changed," Navidi, who was named man of the match after an all-action display, told the club website.
"The confidence is there but we are slipping off a few points and that is costing us. There is still much more we can do out in the pitch.
"We are aware that some games are slipping away and costing us. Hopefully we can now move into the European games and take it forward, build momentum and then come back into the GUINNESS PRO12 with some big wins.
"The result is hugely disappointing but the spirit shown by the boys for that game was absolutely outstanding," he said.
"We dug in, with only 13 men on the pitch at one point, and I felt we did well considering who we were playing."
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