GLASGOW survived two yellow cards, a penalty try and a late Cardiff onslaught to claim maximum points at the Arms Park.
Finn Russell kicked a third penalty to give his side a 35-23 lead, just moments after skipper Jonny Gray grabbed his team’s bonus-point try with less than five minutes remaining.
Yet a brief moment of panic turned what should have been a comfortable win into a frenzied climax in the Welsh capital.
Stuart Hogg stretched out a hand to block Rhys Patchell’s pass and was given his marching orders in the 79th minute.
And with two Cardiff team-mates waiting out wide to score, Italian referee Marius Mitrea ruled a penalty try and triggered a full-blooded assault that stretched deep into injury-time.
It was the second time Glasgow were down in numbers after Ryan Wilson paid the price for his team’s indiscretions just moments after coming on as a replacement. Yet the 14 Warriors held out for a deserved win.
Head coach Gregor Townsend said: “Our indiscipline almost cost us this win. The first yellow made life harder for us and then we had to defend right at the end with 14 men. The players on the pitch had to put in a huge effort, but it’s something we have to look at.
“We always review the penalties we concede and there are plenty to look at this time. When you give away 19 penalties and two yellow cards, you have to ask questions.
“We put ourselves under pressure and let the referee award penalties against us. And it would certainly make life easier if we kept 15 players on the pitch. The players were out on the field for a long time after the game and there’s a lot of work to do to improve. We will need to be much better in that area over the next few weeks.
“But a hallmark of this side has been its resilience. I’m proud of the way they reacted.
“They weathered the storm at the first yellow card and came back to score tries. And they defended for what seemed like a hundred phases at the end. This was an important win, especially away from home and a bonus point was great.”
Russell opened the scoring with a penalty inside three minutes after Josh Strauss was twice denied.
But Patchell made the most of a stiff breeze at his back with a succession of penalties to lead 9-3 after 20 minutes.
However, Alex Cuthbert was penalised for challenging Stuart Hogg off the ball to hand Glasgow a chance from close range.
The Warriors forwards were held up over the line but Grayson Hart’s half-break was followed by Leone Nakarawa.
The Fijian lock stretched out an arm to score on 26 minutes, but Russell missed the chance to take the lead with the conversion.
Blues responded five minutes later with a well-worked try. Dan Fish was twice involved in the move. The full-back switched direction to release Tom James before his off-load to Patchell opened space for Gavin Evans to score.
Patchell missed the conversion but used the wind expertly to guide a penalty kick from the half-way line through the posts for a 17-8 lead shortly before the interval.
But there was still time for Tommy Seymour to break clear, stepping through a crowd of defenders. Nakarawa’s pass was given the benefit of the doubt by the video official and Taqele Naiyaravoro surged over from ten metres out.
Russell converted and kicked a penalty less than a minute into the second half to hand Glasgow the lead for the first time.
Patchell reclaimed the lead for Blues with two penalties to punish Glasgow replacement Ryan Wilson’s yellow card.
Once back to full strength, Glasgow again mustered a comeback with two tries in the space of five minutes from their forwards. Prop Ryan Grant crashed over before skipper Gray barged over six minutes from time.
Russell kicked his third penalty and the game looked to be over at 35-23 before the penalty try set up a grandstand finish.
Cardiff: D Fish; A Cuthbert, R Lee-Lo (J Evans 76), G Evans (T Isaacs 46), T James; R Patchell, L Williams (T Knoyle 77); G Jenkins, K Dacey (M Rees, 55), T Filise (C Mitchell 55), L Reed (J Hoeata 55), J Down, E Jenkins (M Vosawai 74), J Turnbull, S Warburton.
Glasgow: S Hogg; T Naiyaravoro, M Bennett, P Horne, T Seymour (J Bulumakau 46); F Russell, G Hart (M Blair 56); G Reid (R Grant 58), P MacArthur (J Malcolm 79), S Puafisi (Z Fagerson 52), L Nakarawa, J Gray, J Strauss (G Peterson, 70), A Ashe (R Wilson, 52), C Fusaro.
Referee: Marius Mitrea (Italy). Attendance: 5,704.