It was a tough day at the office for Leicester who struggled to find their grove in Crawley and fell to their third defeat of the Barclays Women's Super League season and currently sit eighth with five points.
Manager Amandine Miquel made three changes to the Leicester line-up that beat Everton before the international break, with Janice Cayman and Asmita Ale coming in, along with Chantelle Swaby to make her first WSL appearance since joining the Club; the trio replacing CJ Bott, Saori Takarada and Yuka Momiki.
Lining up in a 5-2-3 formation for the first time this campaign, Cayman was occupying a central forward position with Shana Chossenotte and Deanne Rose on either flank, while looking to neutralise Brighton's threat of committing players forward.
Ten minutes in, the first attempt on goal fell to the hosts which clever play down the right wing before Vicky Losada was supplied the ball in the City box, but the Spaniard saw her effort fly over the bar.
The Foxes backline was then beaten when Parris put Brighton in front. Losing her defender inside the box, the former Manchester United striker was there to head home; the ball clipping the post on its way in.
Unable to find any way through the Seagulls' defence, set up in such a defensive formation, the final chance of the first half fell to Parris once more, when England international Fran Kirby played the ball in to the path of the goalscorer but her connection didn't trouble Janina Leitzig.
It was the home side applying the pressure from the restart, Parris forcing a low save from the German 'keeper before Leicester worked themselves into a promising position, but Ale had strayed into an offside position before being able to play the killer pass.
At the hour mark, Leicester changed approach and introduced Momiki and Hannah Cain, who is building up her fitness after returning from a second career ACL injury, before Miquel's side were forced into more changes following Sam Tierney's unfortunate withdrawal on a stretcher.
City's best chance of the final minutes came from the Welsh forward who tested Sophie Baggaley with a powerful effort at goal, but could only find the gloves of the home 'keeper.
After seven minutes of added time, the referee brought an end to proceedings, confirming a loss for Leicester who will look to bounce back next Sunday when they travel to the capital to face West Ham United at Chigwell Construction Stadium for a 2pm GMT kick-off.