Jehan Mubarak scored an unbeaten 60 to guide Sri Lanka to a narrow two-wicket win over Zimbabwe on Friday, giving the visitors a 4-0 lead in the five-match series.
Zimbabwe, put in to bat, were skittled for 146 in 46.3 overs as spinner Ajantha Mendis took six for 29.
The only bright spot for the home team was an innings of 32 by all-rounder Keith Dabengwa.
Sri Lanka then slumped to 116 for seven but Mubarak stayed cool to steer his side to victory with 15 balls to spare.
Pacemen Tawanda Mupariwa and Elton Chigumbura took three wickets apiece for Zimbabwe.
The final match is also in Harare on Sunday.