The home side began the second half on the front foot and worked a number of chances in the early proceedings.
The best of those openings came via Isobel Goodwin, who made the most of loose play from Liverpool at the back.
Goodwin shot at an empty goal from the edge of the box after stealing the ball and Jenna Clark retreated just in time to get enough on her effort to deflect the ball onto the post.
Lucia Corrales then signalled another threat, shooting over the bar from a tight angle, before Grace Geyoro first worked Rafaela Borggrafe into a save in the area, ahead of seeing a rebound blocked and cleared away.
Goodwin again threatened from a dead ball situation, guiding a header over the bar as the game continued, while Kosovare Asllani saw her lifted shot cleared away by the Reds.
As the contest looked to be heading for a draw, London City earned themselves a penalty in the closing minutes of the match.
Parris sprinted forward to follow in a ball over the top of the defence and Borggrafe came to meet the danger, though was deemed to have taken out the attacker, leading to a penalty kick.
Elena Linari stepped up to convert via the underside of the crossbar, which secured the points for the Lionesses in the final minute of normal time.
Team
Liverpool: Borggrafe, Fisk, Bonner, Clark, Risa, Nagano, Kerr, Höbinger, Holland, Enderby (Olsson, 62), Kapocs (Roman H, 90).
Subs: Kirby, Evans, Szymczak, Lundgaard, Maclean, Silcock.
Next up
The Reds will return to Anfield in their next WSL outing of the 2025-26 campaign. Liverpool will host Manchester City in L4 in a 4.45pm BST kick-off on Merseyside.
Supporters can grab their tickets to attend the fixture here.