Queen of the South recorded their fifth straight victory in all competitions with a win at home to Ayr.
Michael Moffat almost gave the visitors the lead after 15 minutes, but Doonhamers goalkeeper Lee Robinson beat away his left-footed effort.
Just a minute later, the table-toppers were ahead, as experienced defender Ryan McGuffie got on the end of Chris Mitchell's pin-point free-kick to head home his second goal in as many games.
Allan Johnston's side were inches away from doubling their advantage after 26 minutes, when Nicholas Clark headed Derek Young's cross narrowly over the bar.
The former Peterhead man was not to be denied however, and he tapped in his 13th goal of the season ten minutes after the break to extend the hosts' lead.
Paul Burns should have given the league leaders an unassailable advantage three minutes later, but he blazed Daniel Carmichael's back-post cross well wide, as Johnston's men continued their unbeaten run in the league this season.
Queen of South: Robinson, McGuffie, Durnan, Higgins, Mitchell, Burns, McKenna, Young, Carmichael (Hopkirk 83), Lyle (Orsi 84), Clark (Reilly 83).
Subs Not Used: Atkinson, Black.
Goals: McGuffie 16, Clark 55.
Ayr: Brown, Hunter, McAusland, McCann, Twaddle, Sinclair, Crawford, Wyllie (Shankland 79), Moffat, Mackinnon (Winters 63), Roberts.
Subs Not Used: William Muir, Ross Robertson, Brownlie.
Ref: Euan Anderson