Both sides struggled to create any meaningful opportunities in the opening 20 minutes until Stewart Downing fired wide from 20 yards.
Swansea then began to enjoy the better of the possession and could have taken the lead on 30 minutes.
De Guzman was fed through by Nathan Dyer following a quick break, but the midfielder overhit his clever chip when through on goal.
However, it mattered little as Flores headed in minutes later to put the Swans in front.
Swansea instead extended their advantage as Nathan Dyer capped a counter attack with a cool finish past Brad Jones on 75 minutes.
Liverpool pulled one goal back with 10 minutes to play through Suarez's header from Gerrard's corner, but Swansea sealed the win in the final minute of injury time when De Guzman tapped in.