Former world No. 4 Kei Nishikori's return to the ATP Tour after a lengthy injury absence ended in a first round 6-3, 6-4 loss to Sebastian Ofner.

Nishikori has barely played on the tour in the past two years, with his last appearance on the ATP Tour coming at Atlanta in July.

Given a wildcard by organizers, the 2016 Miami finalist was, not surprisingly, a little off the pace against the 40th-ranked Austrian as he struggled to replicate his practice form.