Harlequins director of rugby Conor O'Shea has described Friday's Heineken Cup clash with French giants Toulouse as "the ultimate test".
Quins have won 14 out of 14 games so far this season, their most recent victory coming at Wasps on Sunday.
However, Toulouse lead the French Top 14 and have won Europe's premier competition a record four times.
"We'll see where we are as a team on Friday," O'Shea said. "They're the greatest side in Heineken Cup history."
O'Shea said Toulouse's budget 'dwarfed' Harlequins' finances.
"It's the ultimate test - they can pick two sides packed full of full internationals, world-class superstars," he said. "If you're not going to enjoy playing rugby in that kind of environment, you shouldn't be around."
Quins captain Chris Robshaw described Toulouse as "the Real Madrid or Barcelona of rugby", adding: "As a player you want to test yourself against these sorts of teams. It will be a great test in terms of seeing how far we've come."
O'Shea balked at the suggestion his side might be tired following their hard-fought victory over Wasps at Adams Park, saying the problem was finding a way of "holding the players back".
"The energy will take care of itself because the players can't wait and the supporters are no doubt counting down the days," the Irishman added.
"We're not suddenly a great side if we manage to win and we're not a bad side if we lose, but for the club, the supporters and the players, this is where you want to be - Toulouse, on a Friday night at a packed Stoop. Could you ask for better?"
O'Shea, who took over at The Stoop in the wake of the 'Bloodgate' scandal that led to the resignation of predecessor Dean Richards, was also keen to stress that, despite his side's flying start, they had not achieved anything yet.
"The players have worked incredibly hard, the coaches have done an incredible job, but there's also the knowledge we've done absolutely nothing.
"Yes, we've won a few games but you don't win anything in December, you put yourself in the position to win things in May.
"The guys are very down to earth and know that if we take our eye off the ball we'll come a cropper and suddenly all the good work will come to nothing.
"If anyone in this place thinks they've done anything to date, they're sorely mistaken. But the group, led by Chris Robshaw, will not allow that to happen."
Harlequins, who qualified for the Heineken Cup by winning the second-tier Amlin Cup last season, and defending French champions Toulouse are joint-top of Pool 6 with eight points apiece.