The Crusaders were aware the Highlanders would be desperate, and that was obvious in the game.
"They were desperate, they were hungry and they had opportunities to win that many times. You don't often see Hunty miss those kicks, so 17-17 it's a different game," Robertson said.
"But we hung in there and that's what you've got to do to win comps."
Robertson said they hadn't achieved the good start they wanted to the game.
"We put pressure on ourselves as much as they put it on us," he said.
"We didn't execute the little things. We defended for what felt like 20 minutes, got up the other end and a little knock-on by Bryn [halfback Bryn Hall]. He'll be gutted with that because we were putting pressure on them, then they came back.
"They were brave, they were Highlanders, tough, and it was a typical southern derby," he said.
They lost the kicking and aerial battles as well. They resorted to relying on their defence at critical times and winning some crucial moments.
Their scrambled defence, and their ability to repeat the process, was good, he said.
But there were areas of lack of discipline that proved costly. However, the spirit of the side wasn't broken.
"We're pleased but not satisfied," Robertson said.
Usual Highlanders linchpin first five-eighths Mitch Hunt had kicking issues near the end of the game, missing a kickable penalty goal and kicking the ball dead when searching for a goalline lineout, but coach Tony Brown supported his vice-captain.
"Hunty is a big part of our team…sometimes the weight of the world is on his shoulders, and you can sort of see him playing that way sometimes," he said.
"It's definitely not for a lack of effort. He just wants to win so much, and I can't fault him for that."
The Highlanders had the chance to break their run of losses, a point rival coach Robertson acknowledged.
Brown said: "It's always frustrating when you lose, and it's very disappointing and hard to get over a loss, especially when you should have won. The boys will feel that for the next couple of days.
"We've played a couple of poor games this year, but the majority of our footy has been outstanding.
"If little things go our way, we're going to win. We can't even get a call, we can't get across the line when it matters, and that's the difference," he said.