A lone goal from Kiko Seike, at the start of the second period, was enough to condemn Rick Passmoor's side to a seventh consecutive WSL defeat at King Power Stadium.
There was one change from the side beaten by Aston Villa last weekend, with Asmita Ale missing out with illness, as Sarah Mayling returned to the starting XI, while Emily van Egmond and Sari Kees were back in the matchday squad.
Goalless at the break
One goal separated the two sides on Sunday.
Kicking off at the more unusual time of 3pm, the rain was having the biggest impact, causing a cagey first opening period, which saw both teams try to stabilise themselves although it was the visitors who were on top.
Pushing the Foxes hard in our own half, there was a large spell of dominance from Brighton, in which we had to be alert defensively to deal with the crosses and efforts put into the box.
Struggling to find a way to link up the passes and move up the field, we found ourselves on defensive duty for most of the half, but went into the break goalless.
Brighton find the opener
The Foxes are four points adrift at the bottom of the WSL.
The rain came to a stop over half-time, but it was the Seagulls who took advantage first, scoring three minutes after the referee's whistle, after some clever play inside the box led to the Japanese forward finding the net.
The travelling side took advantage of this and went in search of a second and would have found one about 10 minutes later, if not for Sarah Mayling, who made a brilliant last ditch attempt at a block.
As the game progressed, we looked to get back into it, making some positive moves through Alisha Lehmann and Noémie Mouchon, but after six added minutes, it was Brighton who took all three points.
International duty returns
Our next game is in four weeks time.
Not long after our last international break, another one appears in the calendar now with plenty of our players jetting off around the globe to join their respective camps, putting the WSL on pause until the end of April for us.
Up next, on Sunday 26 April (12pm BST kick-off), we travel to seventh-placed London City Lionesses, in what is turning into a crucial game, with Leicester remaining bottom of the WSL, and four points behind next closest, West Ham United.
To get tickets for our upcoming home and away games, click HERE.