Nakashima broke for 6-4 after a tight opening, saving two break points in a hold for 2-1 to edge through a tense set.
Cobolli broke for 1-0 and again for 5-4, taking the set 6-4 despite Nakashima's break for 3-3 in a competitive second.
Cobolli broke for 4-3 and held for 6-4, saving two break points in that final hold, to clinch the match after Nakashima saved two of three break points in the break.