Rayner said after the first over when he saw the mood Harding was in, he put five fielders back to the boundary.
"[Momentum's] still with us, definitely, probably the time thing is on our side.
"They are chasing the win from now on, which puts the pressure on them, not us."
He was pleased the team had adjusted to playing the longer format to make a 300 plus total.
"I said to the guys, 'every over we bat is as good as every run we score', as it takes time from the game.
"It's all up to Tech now, we can only react to what they do."
Although trailing by 244 runs, Tech manager Andrew Lock said ideally they would have to keep batting well enough to declare while still slightly behind to give themselves a chance of bowling Marton out in a day.
"Bearing in mind we got 80-odd in 13 overs, we probably were more positive than they are.
"We were aiming for around about 100 for the end of the day - a little short of that."
He was pleased with Tech's fight back in the latter part of the afternoon.
"The last 20 overs, new ball, we got a couple of them.
"Once McIlraith was out it was a little bit easier, although he should have been out sooner."
Day two will resume on Saturday.