The victory saw Forest win their round of 16 tie and reach the Europa League quarter-finals.
"Just buzzing to be through. Penalties are always tough and nervy, but the lads stepped up," Yates said.
"The journey's not over yet – we're still dreaming. Considering the changes, it just shows the strength we have and the spirit.
"At this stage of the season, that's what it's all about: showing togetherness, fighting for each other. A lot of lads today and haven't played many minutes will now be looking for more."
On the away support, the midfielder added: "From minute one, they really helped us.
"Momentum at this stage of the season is huge. We're not going to get ahead of ourselves. Hopefully, we can keep building and keep getting wins."