Second half goals from Johanna Maher and sub Karen Hegarty helped Westmeath to overturn a two-point half-time deficit and lead by 2-5 to 0-8 with 49 minutes remaining.
Sub Daena Clerkin hauled Cavan back into contention with a 54th minute score before a brace of frees from captain Aisling Doonan restored parity for the Breffni ladies.
Doonan was the pivotal figure for Cavan, top-scoring with six points and producing a magnificent display, particularly in the first half. The sides were level twice in the first half before points from Murphy and Doonan opened up a 0-5 to 0-3 interval lead for Cavan.
Scorers for Cavan: A Doonan 0-6 (2f, 1 sl), R Murphy, R Crowe, B Sheridan (f), D Clerkin & C Kearns 0-1 each.
Scorers for Westmeath: J Maher & K Hegarty 1-1 each, R Kearney 0-2, E Morris 0-1.
CAVAN: C McCutchon; C O’Reilly, C McGlade, C Kearns; R Murphy, P Crowe, D English; R Crowe, A Cornyn; R O’Keeffe, B Sheridan, E Costin-O’Connor; B Boylan, C O’Reilly, A Doonan.
Subs: S Greene for Cornyn (35), G Smith for O’Keeffe (46), D Clerkin for Boylan (47), C Gray for Crowe (56), A Traynor for Costin-O’Connor (58).
WESTMEATH: G Leahy; A Martin, G Kearney, T Durkan; K Boyce-Jordan, J Rogers, M Malone; M Annie-Foley, F Claffey; E Finn, R Kearney, L Brennan; L Walsh, K Somers, J Maher.
Subs: K Hegarty for Somers (h.t.), E Morris for Brennan (42), A Brady for Boyce-Jordan (42).
Referee: G Corrigan (Down).