A frenzied and end-to-end affair appeared destined to end without the net rippling once, but in the ninth minute of second-half added time, Darwin Nunez - just back from injury - nodded home to seal Liverpool's first-ever Premier League win away to the crestfallen Tricky Trees.
A trio of hitherto injured players in Nunez, Dominik Szoboszlai and Wataru Endo were all passed fit to make the visitors' bench, while Divock Origi led the Forest line over another erstwhile Liverpool man in Taiwo Awoniyi.
The Belgium international - scorer of several famous goals during his time at Anfield - almost notched one against his beloved Liverpool in the 14th minute, but his 25-yard effort fizzed slightly wide of the top corner.
An open start to the contest also saw Luis Diaz - with the help of a deflection - fire just past the post in the 17th minute, before the in-form Caoimhin Kelleher made a top save with his feet to thwart Anthony Elanga during a 22nd-minute one-on-one.
Spurred on by the Irishman's latest exceptional stop, chances soon began to come thick and fast for Liverpool, but Jurgen Klopp's men forgot to dust off their best shooting boots, firing eight shots but none on target in the first half.
Neither manager made any substitutions for the start of the second period, but Klopp would unsurprisingly blink first, bringing on the newly-fit Endo and Nunez just before the hour mark for Andy Robertson and full Premier League debutant Bobby Clark.
Renowned chaos agent Nunez immediately got stuck into the thick of things, hitting the side netting from an acute angle in the 62nd minute - a fate shared by Cody Gakpo eight moments later.
In between those two opportunities for the Reds, Elanga also failed to find the mark with a wide attempt in the 66th minute, and the end-to-end action continued as Nunez headed over the top in the 73rd.
Not for the first time at the City Ground, Kelleher was Liverpool's saviour as he prevented an 81st-minute strike from Callum Hudson-Odoi creeping in at his near post, and both sides would be granted eight additional minutes to try to find a winner.
The all-important strike nearly arrived in the fifth additional minute, but Sels produced an amazing reaction save from Nunez's deflected header, before appeals for a Forest spot kick at the other end were waved away - much to the hosts' chagrin.
One last set piece came Liverpool's way in the ninth minute past the 90, and while Forest partially dealt with the situation, Alexis Mac Allister kept the ball alive on the edge of the box and delivered an inswinging cross for Nunez, who got just enough connection on the ball to beat a flat-footed Sels.
Unrestrained celebrations behind the Belgian's goal began as Liverpool temporarily built up an unassailable lead at the summit, but in contrast, a heartbroken Forest - who had first-team coach Steven Reid sent off during heated scenes at the end - remain just four points clear of the drop zone in 17th.
A long trip south to Brighton & Hove Albion awaits Nottingham Forest on March 10, while Liverpool resume their quest for Europa League glory on Thursday, heading to Sparta Prague for the first leg of their last-16 tie.