Clarke has tried to downplay the significance of Albion losing three games in succession after climbing to third in the table last month.
But the former West Ham number two knows the significance of the Baggies recapturing the winning habit sooner rather than later.
Clarke said: "I don't think it is a massive test. The test for me as a number one came when I walked into this job in the summer.
"That was the big test. We started well this season and, if you took out the defeats we've had and spread them over a course of the season, everyone would be saying we are doing fantastic.
"That's the line I tend to stick with. If I had been offered the top six in mid-December, I would have been pleased with the points tally we've got.
"But it is up to us to make sure the bad run stops now and we start to pick up more points.
"The players this week have been positive, not dwelling on the three defeats. They are looking forward to the run of games coming up.
"It would have been nice if we could have kept the good run going a little longer, but we didn't, and we have to make sure the next run starts on Sunday.
"We know we've lost the last three because everyone keeps telling us, but we are not going to forget that anyway. We know we have to address it this weekend."