World No. 12 cites one key quality combating slump.
Gold medal champion getting in tune in Acapulco.
Nightmare opponents don't scare Swiss anymore.
Former world No. 2 joins iconic Italian sportswear brand.
Kei Nishikori says there's a simple reason Naomi Osaka will cope with life at the top.
The Swiss will meet Germany's Philipp Kohlschreiber in first-round action at Dubai.
The Argentine says he needs to rest his right knee and plans to return to action at Indian Wells.