HELSINKI (Reuters) - Finland's Nokia said its fourth-quarter results were better than expected and that the mobile phone business achieved underlying profitability, a rare spot of good news for the struggling handset maker.

Quarterly net sales in devices and services was about 3.9 billion euros ($5.09 billion). It sold a total of 86.3 million devices. Smartphones accounted for 6.6 million units, of which 4.4 million were Windows-based Lumia handsets, the company said.

Nokia shares surged 16 percent to 3.48 euros by 1315 GMT. ($1 = 0.7667 euros)

(Reporting by Ritsuko Ando; Editing by David Goodman)