The 25-year-old however does accept that the lack of a killer instinct is contributing to the disappointing results, with Greig Laidlaw's try in Cardiff their first in five internationals.
Rennie, though, is thankful they have the chance to put that right at home to France on Sunday and is confident Robinson can lead them to glory at Murrayfield.
Rennie told The Scotsman: "I think he is still very much the right man for the job. The coaches are very good, it's just a matter of tweaking a few things and, hopefully, it will all click.
"We have been making line breaks and not finishing two-on-ones. We have been compounding errors and, when you have a couple of mistakes, that is when these teams score tries.
"We are frustrated, everyone realises we've made a huge effort but there's not much come from it yet. It is very frustrating where we are right now, who likes losing?
"I don't think it's ever fun losing but, at the same time, I feel very proud and very happy to be in this position where we can try to put it right.
"At the start of the Six Nations we were all riding high, looking forward to the England game again, and we get kicked back down again. You're playing with such highs and lows.
"The nice thing is that we have an opportunity to put it right, I suppose, and get back to the highs. On those big occasions you experience big highs when you win and big lows when you lose."