Missing key players through injury, Karen admitted 'it wasn't our best performance' as Brighton stormed into a 3-0 lead by the break before running out 4-0 winners at the Withdean Stadium.
The ladies now take on Millwall in the FAWPL South at Harlow Town FC on Sunday, kick-off 2pm.
"We have a few injuries to key players going into the new season which has set us back in terms of preparation, but this was a good indicator of the level we need to raise our game to," said Karen.
"We'll continue to work hard and look forward to Millwall on Sunday. I’m hoping for a better team performance."
Brighton broke away from a Spurs corner to open the scoring after 20 minutes, Faye Rabson finishing well.
Jenna Schillaci saw a free-kick saved by Lily Agg before Brighton's Kim Stenning blasted over from close range. Stenning soon made amends to make it 2-0, Rabson was denied one-on-one by Jo Ayre but Brighton added a third before the break, Robyn Downie unfortunately putting through her own net.
To their credit, Spurs ralled in ther second half and came out more determined, although Stenning completed the scoring in the 71st minute.
Team: Ayre, Albertsen (O'Halloran, 83), Orridge-Golding, Downie, Heath (Wilson, 60), Schillaci, Cheeseman, Pittuck, Burr, Thomson, Baptiste.