Cardiff Blues had to play with 14 men for 30 minutes as referee Ben Whitehouse hit them with three yellow cards in a 17-3 defeat to regional rivals the Ospreys.
The visitors also picked up one yellow card but had a second-half penalty try to thank for seeing them over the line in the second round of three weekends of Welsh derbies in the Guinness PRO14.
Having been pipped 16-14 against the Scarlets, they dominated up front to win comfortably.
The Blues were seeking to make it three wins in a row for the first time against the Ospreys since the regions were formed in 2003 and drew first blood at the end of a cagey first quarter which saw both sides kicking for position and mistakes.
The breakthrough came in the 21st minute when Hallam Amos bucked the kicking trend and led a breakout from his own half that saw Aled Summerhill and Tomas Williams carry into the Ospreys 22.
The forwards piled in and the visitors had to concede a penalty at a ruck to hold their line. Up stepped Jason Tovey and over went the first points of the game.
In the build-up to the move the Ospreys Welsh international centre Scott Williams picked up a left shoulder injury when he was cleaned out by Josh Adams and he had to leave the field. Tiaan Thomas-Wheeler came on to replace him.
Back to back penalties by the home side then allowed Stephen Myler to kick the Ospreys into the right corner and a well-set driving line-out maul ended up with hooker Ifan Phillips bagging the first try of the night. Myler added the extras to give his side the lead in the 32nd minute.
Dan Lydiate then had a terrible few minutes as he first conceded a penalty for taking out a player without the ball from the re-start. Tovey kicked to the corner and the Blues had two close-range line-outs to try to reply in similar style.
A crooked throw ruined their plans and then a scrum penalty conceded by former Osprey tight head Dmitri Arhip allowed the visitors to clear their lines. The Blues had one last attack before the break after Lydiate had been given a yellow card for leading with his forearm in a ball-carrying charge into Tovey.
Once again the Ospreys defence held out and they were good value for their slender interval lead. Myler was just wide with a kick from 45 metres five minutes into the second half and then it was the turn of the Blues to play with 14 men.
As Lydiate came back onto the field after his 10 minutes in the sin-bin, home lock Seb Davies trudged off after pulling down a line-out. Myler extended the lead with a simple penalty in the 56th minute and the Ospreys were dictating the pace of the game.
The extra man paid off at a line-out 10 metres from the Blues line and when the driving maul was pulled down illegally, Arhip got another yellow card and Whitehouse awarded a penalty try.
Arhip’s replacement, Scott Andrews, then saw yellow in the 68th minute at a buckled scrum to briefly reduce the home side to 13 men.
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