Despite dominating the majority of the game, the Magpies, who sold Andy Carroll for £35m in the transfer window without securing a replacement, were unable to beat former England international Paul Robinson in the Rovers goal.
Newcastle started with the same side that capitulated in the first half against Arsenal last weekend, but their performance before the break at Ewood Park represented a marked improvement on the previous week's events.
The Magpies were almost ahead in the fifth minute, but Kevin Nolan was unable to reach Joey Barton's pull back after good work from Jose Enrique down the left.
There was a scare five minutes later when Roque Santa Cruz headed against the post after Christopher Samba had headed on Robinson's long clearance, but Newcastle hit the woodwork themselves shortly after.
Enrique's fantastic long ball sent Peter Lovenkrands galloping clear down the left, but while the Dane's lobbed shot beat Rovers goalkeeper Paul Robinson, it rebounded to safety off the crossbar.
Leon Best fired a first-time volley wide shortly before the interval, and Fabricio Coloccini came close to scoring one of the goals of the season nine minutes after the break.
The centre-half controlled Joey Barton's floated corner, lifted the ball over Jermaine Jones' head, and hammered in a left-footed volley that Robinson did well to save.
Newcastle dominated possession throughout the second half, but failed to carve out as many chances as they had created before the break.
They were rarely troubled at the back, although Steve Harper had to be alert to smother a Samba header following another long free-kick from Robinson.
BLACKBURN (4-4-2): Robinson; Salgado, Samba, Nelsen, Olsson; Jones, Dunn (Emerton 65), Nzonzi, Hoilett (Pedersen 46); Santa Cruz (Roberts 46), Kalinic.
Subs (not used): Bunn (gk), Grella, Hanley, Benjani.
NEWCASTLE (4-4-2): Harper; Simpson (Perch 76), Coloccini, Williamson, Enrique; Barton, Tiote, Nolan, Gutierrez; Best (Kuqi 90), Lovenkrands (Ranger 77).
Subs (not used): Krul (gk), Campbell, Ferguson, Guthrie.