Liverpool 1 Unirea Valahorum Urziceni 0
The Anfield crowd almost had a goal to cheer in the first minutes as Dirk Kuyt's pass released skipper Steven Gerrard and his first-time short forced a fine save from visiting keeper Giedrius Arlauskis.
Ten minutes in Kuyt tested Arlauskis with a flashing drive from the right of the penalty area, forcing the keeper into a smart, low tip-away.
A subdued atmosphere on Merseyside saw the game then slow down, although the home side seemed to be in control most of the time.
They forced a series of corner just past the half-hour mark, but were unable to make the breakthrough, with N'Gog also having a fine shot on the turn deflected away.
Unirea offered in the way of an attacking threat as a poor first half drew to a goalless close.
After the restart Liverpool again began the brighter, but were still unable to carve out any clear chances.
On the hour mark Razvan Paduretu found space on the edge of the home area, but was unable to direct his left-foot shot anywhere near Jose Reina's goal.
Soon after Fabio Aurelio drew a fine low save from Arlauskis with a stinging left-foot drive from 30 yards out.
Martin Skrtel headed over from a corner 20 minutes from time, before N'Gog nodded wide from an Aurelio cross from the left and then shot over following a goalmouth scramble.
Nine minutes from time the Reds finally made a breakthrough as Ryan Babel's deep cross from the left was headed down by Daniel Pacheco and N'Gog nodded home from less than five yards out.
Gerrard fizzed a superb half-volley narrowly wide five minutes from time, but Liverpool had to settle for a narrow advantage to take to Romania for next week's second leg.