"It has been a tough journey and we do not want to end it here just yet. All the African countries we have travelled and the challenges along the way have made us stronger,” Modiba told the Sowetan.
They have surprised all and sundry by getting as far as the last four, with a place in the final 90 minutes away.
However, they failed to make their home dominance count at the start of the month in the first-leg when they scored late to force a 1-1 draw in Tshwane.
They now have to encounter an intimidating atmosphere and a hostile crowd in Tunis, but Modiba says they have a perfect plan to upset the upper cut, let alone the continent.
"For this game the coach will overload the wings and put them under pressure. They are not good on the ball," Modiba said.
"We have pacey players so we can create chances just like we did in the first leg. But this time we will bury them,” Modiba added.
Having just won the MTN8, it has eased their confidence and morale ahead of the massive test awaiting them in North Africa.
"Since winning the cup, spirits have been high. We want that feeling again but this will be bigger as we are representing the whole nation,” Modiba said.
United will need a 2-2 draw to ensure passage to the final, and Modiba will have to step up like he did away to TP Mazembe in the group stages when he found the net in Lubumbashi.