Their fifth win of their run was a lesson in grit rather than grace as they pulled off a rearguard defence at the death to down Welsh rivals Newport Gwent Dragons 12-7.
And even with Rugby World Cup stars such as Alun Wyn Jones, Justin Tipuric and Scott Baldwin back in the team, Gibbes admits his side have not yet reached the levels required of them.
"It's the performance we're after, and even with the big names coming back in we still haven't performed to where we need to be as a team," said Gibbes.
"As a squad, all of us have to have a good look at that. Clearly we're still climbing the ladder in the Pro12 but we need a good performance to get the result against Leinster.
"We're going up the ladder rather than down which is pleasing, then we chase that top four."
Meanwhile, a shoulder injury to another World Cup star in Dan Lydiate is not as bad as first feared, according to Gibbes.
The flanker sustained the knock in the victory over the Dragons, while centre Josh Matavesi and prop Dmitri Arhip were also casualties ahead of this week's clash with Leinster.
"We're still checking day-to-day with Josh, we're hoping that's not too bad with the calf," added Gibbes."Dmitri, it's his ribs and those injuries take a while to get right.
"But there's nothing broken with any of them which is good, or torn in the case of the calf, so we've just got to manage it day-to-day.
"Dmitri's going to struggle but the other two we'll assess as we go. Lydiate has got a stinger and he's just working through that day-to-day."
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