The England international, sidelined since October with an ankle problem, played the final 21 minutes but could not inspire a change in fortunes against the Premier League's bottom club.
Kenny Dalglish's side, although unbeaten at home this season, have now drawn six and won three and been held five times in the last six outings at Anfield.
And had it not been for Maxi Rodriguez's 11th goal in his last 12 starts the result could have been more embarrassing after Charlie Adam had put through his own net on the stroke of half-time.
A familiar pattern of failing to take chances emerged very early on but the difference here, throughout the whole side, was the lack of spark and crispness which the Reds have usually had.
Luis Suarez's second-minute free-kick which sailed just over set the tone before Adam sliced an ambitious volley from outside the area which gave Mark Bunn, deputising for the injured Paul Robinson, a much easier save than he could have anticipated.
There followed two efforts from Suarez, one into the side-netting from Glen Johnson's pass, and the other missing the target completely with a left-footed shot from a similar position on the right of the penalty area.
In recent months opposition goalkeepers have made a habit of saving their best performances for Anfield and Bunn's point-blank block from Andy Carroll, starting for the first time in four matches, after Downing had kept in Jose Enrique's deep cross had a familiar look to it.
Carroll had a goal ruled out on the half-hour as Suarez was offside and the assistant's flag rescued Bunn from conceding a penalty when he brought down Rodriguez, although it was inactive Suarez and not the Argentinian who had got ahead of the Rovers defence.
Blackburn's attacking was sporadic at best and when they did get a chance to test the meanest defence in the Barclays Premier League they wasted it as Ayegbeni Yakubu's cross from a quickly-taken corner was well over-hit.
In the end they needed a helping hand as, totally against the run of play, Adam diverted Morten Gamst Pedersen's inswinging corner past his own goalkeeper just seconds before half-time.
It capped a disappointing few days for the Scotland international, who also put through his own net against Rovers for Blackpool last season, as he missed a penalty in Wednesday's goalless draw at Wigan.
It took Liverpool eight minutes to equalise.
Downing's cross was cleared only as far as Martin Skrtel who hooked the ball back to the far post where Rodriguez headed in from close range.
The goal gave the Reds the spark they needed and, with Bunn wasting time at every opportunity, Suarez headed wide Downing's corner from a spot very close to where his team-mate had equalised.
A Carroll overhead kick was cleared by Grant Hanley while another Rodriguez far-post header, this time back across the six-yard area was crying out for a final touch with no Liverpool player anywhere near.
Gerrard finally got his long-awaited return to action in the 69th minute when he replaced Adam and ran straight on to curl in a free-kick which was headed over by Rodriguez.
Suarez then headed over Johnson's cross before the England defender was relieved to see David Dunn stab wide after needlessly giving away possession in midfield.
The action intensified as Carroll headed wide Enrique's cross, Rodriguez made way for Craig Bellamy to come on against his former club and Downing rolled a left-footed shot too close to Bunn having been played in by Gerrard.
Liverpool twice thought they had stolen the points in the closing moments, Carroll drawing a fine save from Bunn with a close-range volley and 17-year-old Adam Henley, on his first senior start, clearing off the line after Daniel Agger's header from the subsequent corner.
Such problems cannot be allowed to continue for Kenny Dalglish, who must surely have to address the issue of a lack of goals in the coming transfer window.
Blackburn's players celebrated a hard-earned point at the final whistle but their difficulties - they remain bottom of the table - will probably take more fixing.