Bentley came alive for Rovers in the second half
Two sublime goals from David Bentley helped Blackburn to their first win in five games at the expense of Newcastle.
The Magpies took the lead after the restart when Obafemi Martins headed in Geremi's free-kick from the left.
Bentley equalised for Rovers when he curled in a 22-yard free-kick that left keeper Shay Given rooted to the spot.
The midfielder side-footed his second from 25 yards out before Tugay added gloss to the Rovers scoreline with a poked effort from 15 yards.
The defeat leaves the Magpies without a win in five although the fans, who had recently been critical of manager Sam Allardyce and the players, would have been heartened by the performance.
However, they almost got off to a terrible start when the defence parted to allow Santa Cruz to run through.
Luckily for the away defence, the tall striker clipped his ball wide of Shay Given's right-hand upright.
Apart from that scare and one later in the half that saw a rush-of-the-head moment from Given almost penalised by Bentley from 40 yards, Newcastle were comfortable during the first 45 minutes.
But so were Blackburn, although their defence was made to work a lot harder by the Magpies - especially forwards Alan Smith and Martins.
Rovers had coped admirably with the mid-height balls chipped into their area but manager Hughes would have been left livid straight after the restart when Martins gave the visitors the lead.
The Nigeria striker was left unmarked and flicked in Geremi's free-kick from the left past Brad Friedel.
Within seven minutes Blackburn posted their riposte and they were back in the match.
Left-back Charles N'Zogbia conceded a foul on the edge of the area and up stepped Bentley to curl in a 22-yard effort that left Given stranded on his spot.
Barton should have put the Magpies back into the lead but his shot was smothered during a scramble in the six-yard area.
Martins then missed an even easier chance from four yards when he headed the ball over from a James Milner flick-on.
They were made to regret those missed chances when Bentley, who had a quiet game up until his first goal, fired in Rovers' second.
The England international seized on a loose ball from Stephen Carr's tackle on Santa Cruz and placed a 25-yard low side-foot cross-shot past Given's reach and in off the post.
As legs tired, chances flowed, with Milner seeing his shot blocked from eight yards and Blackburn substitute Morten Gamst Pedersen's diving header beating Given but also the keeper's left-hand post.
With Newcastle pouring forward in a desperate attempt to salvage a point, they left spaces at the back.
And they were exposed in stoppage time by another Rovers substitute, Jason Roberts, who laid the ball into the path of Tugay, who in turn poked the ball past Given from just inside the area.
Blackburn boss Mark Hughes:
"We had to dig in and compete. We saw our way through it and scored some great goals as well.
"It was an outstanding strike from David and an important moment for us as it was the equaliser.
"David also got a good second goal, although his luck was in with the ball hitting the post."
Newcastle assistant manager Nigel Pearson:
"It has been a difficult week and we have come in for a lot of criticism.
"That perfomance gives us some dignity. Two moments of brilliance from David Bentley turned the game for Blackburn.
"If we put in the same energy and commitment, and play good football, then we'll be OK."
Blackburn: Friedel, Emerton, Ooijer, Samba, Warnock, Bentley, Kerimoglu, Mokoena (Reid 66), Dunn (Pedersen 58), Santa Cruz, McCarthy (Roberts 61).
Subs Not Used: Brown, Savage.
Booked: Bentley, Kerimoglu.
Goals: Bentley 54, 67, Kerimoglu 90.
Newcastle: Given, Beye, Rozehnal, Faye (Carr 24), N'Zogbia, Geremi, Butt, Barton, Martins, Smith, Milner, Carr (Viduka 72).
Subs Not Used: Harper, Jose Enrique, Emre.
Booked: Butt, Barton, Milner.
Goals: Martins 47.
Ref: Martin Atkinson (W Yorkshire).