An ill-disciplined Blues have lost 30-22 to the Stormers in Cape Town and almost certainly blown their Super Rugby finals hopes in the process.
A three-game winning run ended for the Blues, who had the better of much of the game but stumbled late, espcially after the sending off of winger Matt Duffie in the 66th minute when he was shown a second yellow card.
The result was relieving for the finals-bound Stormers, who had lost their last four games, including fearful hammerings in three games in New Zealand.
It was just the second loss this season by a Kiwi team against offshore opponents. The Chiefs were also undone by the Stormers in Cape Town, in round seven.
While the other New Zealand sides are on course for post-season action, the Blues' sixth loss from 12 means they'll almost certainly miss the playoffs for a sixth straight season.
Their lack of panache at crucial times has proven their downfall more than once. It was evident again in a tense, testy affair on Saturday (AEDT).
Both teams scored three tries but the goalkicking of Stormers fullback SP Marais proved influential, landing six from seven shots.
The Blues conceded 13 penalties, struggling with the officiating of Jaco van Heerden.
When they held onto possession they were dangerous, exemplified by the remarkable ball skills of Charlie Faumuina.
All Blacks prop Faumuina threw sweet passes to put centre George Moala and hooker James Parsons over for tries midway through the first half to put the visitors 12-3 up.
Impressive Stormers skipper Siya Kolisi responded on the stroke of halftime but the Blues went into halftime up 19-10 when Black Gibson capitalised on a trademark offload from Sonny Bill Williams.
A second Marais penalty was followed by a try from a quick tap and try from Stormers five-eighth Dillyn Leyds.
Duffie's second yellow card was for diving on a prone player, following a first- half offence when his offside play was deemed to be a professional foul.
The Stormers also had their moments of ill-discipline.
Lock Eben Etzebeth was shown a yellow card for instigating an all-in team scuffle in the first half.
Their New Zealand inside centre Shaun Treeby was fortunate not to face further sanction when his high tackle on Piers Francis forced the concussed Blues five- eighth to exit on a stretcher.
Medical staff later said Francis had been unconscious for a short period after the tackle.
Umaga felt Treeby should have been at least shown a yellow card for the sake of consistency and was also riled by some of the other rulings from van Heerden.
However, he didn't want to make excuses for his team and said he will query the rulings later with Sanzaar referee boss Lyndon Bray.
"There were some tough calls that we felt went against us but that's the way it goes," Umaga said.
"The Stormers brought a brutal intensity on defence and made it hard for us to build continuity in our game."
The Stormers, who won their first six games, boast a 7-4 record to remain comfortably on track to win their South African conference.