But, according to the full-back, his side will look to pile the pressure on their opponents under the Sixways lights.
He said: "Quins will be a big threat, they will want to keep the ball, make it quite a loose game, and their number ten Nick Evans will dictate their game.
"But we're going to put any team under pressure, we can beat any side at Sixways and we have shown that we are good enough to do that.
"We've performed well in patches of games so far but, if we can transfer that to a full 80 minutes, we will be winning matches and it doesn't matter who we are playing against - we will come out on top."
Warriors boasted an impressive Friday-night home record last season which saw them win five of their six matches.
And the Warriors vice-captain believes that tomorrow's showdown is a game Worcester will set out to win.
He continued: "We are confident going into it. We just need to iron out some of the things that didn't go so well against London Irish. If we can keep our discipline, we will compete."
Warriors were left frustrated last weekend after being edged out by London Irish in a thriller at Sixways.
But Pennell admits Warriors will be looking to bounce back against Harlequins.
He concluded: "We could have quite easily won that game by 20 or 30 points if we'd have kept our discipline but it wasn't to be.
"We've had a sit down, analysed it, and we will set out to get it right on Friday."
Tickets for Friday's game start from just £19.50 for adults and £11 for juniors and are now available to buy. To purchase tickets call the Warriors Box Office on 01905 459309 or click here.