The 19-14 result was the Nelson Mandela University side's first loss in the round-robin phase of the competition and coach Jarryd Buys said they wanted to bounce back against Rhodes in Grahamstown this week.
Friday's fixture will renew an old rivalry between the Eastern Province-based varsities and Buys said they needed to rediscover their best form against the home team.
"We have spoken about the other teams lifting their games against us, but only until you see it actually happening do you realise that it's the best way to learn what we are facing," he said of the Walter Sisulu result.
"In terms of the individuals and the team that will be a massive wake-up call and it's another warning that you can't take anything for granted.
"There are other teams out there who want it just as badly as we do."
Buys said there was no need to panic, but he acknowledged that they had to rectify what went wrong on Friday.
"We can't just coast along and think the wins are going to keep happening.
"But the attitudes are right and we had a good training session on Monday. It's been a tough couple of days but the guys have to take it on the chin and it's often in adversity that a person's character is shown.
"The way we played on Friday we need to put in a mammoth performance this week.
"It needs to be physical, it needs to be ruthless and it needs to be a case of showing ourselves that what happened on Friday was a once-off."
He admitted they lacked the proper intensity against Walter Sisulu.
"Losing last year's final [to Cape Peninsula University of Technology] was one thing because we actually played decent rugby and fell off in the last few minutes.
"But Friday's result was tough to take. We were flat and very unhappy with how things went and the performance we put in.
"The way it went in the first game [against UKZN] the players perhaps took it for granted that the same intensity was going to be there against Walter Sisulu.
"Each guy was looking around expecting it from the other guy and not doing it himself.
"But now we have to get back up and move onto the next job – and that is our priority in Grahamstown on Friday."