Erin Cuthbert’s late winner against Birmingham City gave Chelsea a three-point lead at the top of Women’s Super League One, with three games remaining.
England striker Fran Kirby put the Women’s FA Cup winners ahead with a fine strike into the top corner.
After half-time, Wales’ Hayley Ladd levelled on the half-volley for the visitors after Jess Carter’s good run.
But Birmingham were denied a point in the closing stages, as Cuthbert slotted in to snatch Chelsea a valuable win.
The unbeaten London club would have moved top of the table with a draw, but victory saw them take full advantage after title rivals Manchester City were beaten at Liverpool on Tuesday.
Emma Hayes’ side will now be champions if they take seven points from their remaining three games – at home to Sunderland, away to Bristol City and away to Liverpool.
Birmingham, who would have gone up to third with a win, had kept Chelsea at bay for the vast majority of the second half thanks to good saves from Ann-Katrin Berger, who denied Kirby, Cuthbert and Maren Mjelde.