Lacasse then swept home her second after a miscued Beth Mead shot, before substitute Alessia Russo headed in.

Arsenal will face Aston Villa in the last four on Wednesday, 6 March.

Manchester City host Chelsea the following day in the other last-four tie, with the final at Molineux on 31 March.

Arsenal's meeting with the Lionesses was originally due to take place on 7 February, but a waterlogged pitch meant the game was postponed just four hours before kick-off.

Later that evening, London City also parted company with head coach Carolina Morace and her assistant Nicola Williams, leaving goalkeeper coach Darren Smith in charge.

The Gunners, who were looking to bounce back from their FA Cup exit at the hands of Manchester City on Sunday, were frustrated by a stubborn home defence for large periods of the first half, with Caitlin Foord twice going close.

Lacasse's 39th-minute opener was slightly fortuitous in the way it landed straight on the Canadian forward's head and deflected off a defender on the way in, but it was what the visitors deserved.

Little's penalty was as clinical as usual and came after Blackstenius was fouled by goalkeeper Grace Moloney, following a poor misplaced pass from former Arsenal defender Emma Mukandi.

Jonas Eidevall's side were patient at the start of the second period but sealed the success when Lacasse superbly curled home a loose ball and substitute Russo powered a header under Moloney moments after coming on.

With the visitors currently third - and six points behind leaders Chelsea - in the Women's Super League, they know this competition may represent their best chance of silverware this season.