I admit I had never heard of Uniqlo until I saw Nishikori wearing the brand. I experienced Uniqlo for the first time on a recent trip to Asia, my first overseas sojourn for over 5 years. I'm not frustrated I can't get my hands on Djokovic's line or any sporting apparel. I'm just happy to now be familiar with Uniqlo clothing. It has replaced every other mainstream apparel retailer on my shopping list. In that sense, I think Uniqlo was right in signing up Djoker - he's made a few more people aware of the brand.
I now can't help but imbue Uniqlo with the same brand halo as Toyota, Seiko et.al - mainstream Japanese brands with solid credibility. (The GAP I view with the same indifference as American carmakers and Zara = a South African-built VW...)