Republican upstart David Storobin clung to a slim lead in the special election to replace disgraced Brooklyn ex-Sen. Carl Kruger, according to a partial recount yesterday.

Storobin, a Russian immigrant and lawyer, led Democratic Councilman Lew Fidler by a mere 143 votes — 10,505 to 10,362. But a few remaining precincts had yet to be recounted, and roughly 1,000 paper absentee ballots also must be tallied, which could take until next week.

A Storobin win would be an upset in the overwhelmingly Democratic district.

Both candidates claimed victory yesterday.