Captain Helen Lilley’s side defeated Durham 5.5-3.5 to add to opening wins against Cumbria and Northumberland.
It means they remain one point clear at the top of the table as they prepare for today’s Roses clash with Lancashire.
Cheshire trail them by a point after beating Lancashire 5.5-3.5 while in day three’s other game Cumbria edged Northumberland 5-4.
Yorkshire had taken a 2.5-0.5 lead from the morning’s foursomes against Durham, with the pairings of Olivia Jackson (Pannal) and Holly Morgan (Hallamshire), and Huddersfield’s Megan Clarke and Nicola Slater, of Lindrick, both winning while Hannah Holden (Lightcliffe) and the hosts’ former Yorkshire champion Megan Lockett returned a half.
Any thoughts that the comfortable lunchtime advantage might lead to an overwhelming victory were quickly disabused as Durham won two of the top three singles, the other seeing Morgan halve her match.
But after Woodsome Hall’s Melissa Wood shared match four to maintain overall parity, Clarke moved to a total of four wins and a half from five matches with a 5&3 afternoon win and Holden was even more convincing, prevailing 6&5.
Sickleholme’s Lilley is scheduled to have Megan Garland available for today’s Roses encounter and tomorrow’s closing match with Cheshire.