Manager Owen Coyle gave 21-year-old Gallagher a starting berth up front alongside Marvin Emnes at Ashton Gate, as Rovers took on the in-form Bristol side.
After a first-half of few chances, Gallagher almost broke the deadlock on 62 minutes. Having found space on the right of the area he whipped a ball across the six-yard box, but it evaded both the onrushing Emnes and Craig Conway.
A minute later Conway almost returned the favour with a teasing cross from the left, however Gallagher was unable to connect at the back post.
The hosts then struck on the 88th minute through Aaron Wilbraham to seal all three points. The veteran striker’s deflected effort wrong-footed Jason Steele to move Bristol City up into sixth whilst Blackburn move down to 22nd.
Elsewhere, Jason McCarthy helped Walsall to a 2-0 victory over Swindon Town in League One whilst Dom Gape played 84 minutes in Wycombe Wanderers’ 2-0 defeat at home to Barnet.
In Spanish Segunda Division, Paul Gazzaniga kept another clean sheet as Rayo Vallecano registered a 1-0 victory at home to Girona to move up to 8th.
SportPesa have four spaces in their corporate box up for grabs for Southampton’s game against Chelsea on Sunday 30th October (kick-off 4pm GMT).
Winners will receive a pair of hospitality tickets to the game against the Blues, as Claude Puel’s men look to stretch their unbeaten league run to six matches.
To be in with a chance of winning, simply click here and register with SportPesa.
Everyone who registers before 9pm on Wednesday 26th October will be entered in to a prize draw, with four winners picked at random and informed on Thursday 27th October.
Southampton extended their unbeaten Premier League run to five matches with an impressive 1-1 draw at title favourites Manchester City on Sunday.
But it speaks volumes for how far Saints have come during manager Claude Puel’s short reign in charge they were disappointed not to leave the Etihad with all three points.
Nathan Redmond scored his third goal of the season after seizing on a mistake by error-prone England defender John Stones to give Southampton a half time lead.
A defensive lap early in the second half to allow Kelechi Iheanacho to smuggle an equaliser denied Puel what would have been a famous win over Pep Guardiola’s side.
The extra hours Redmond is putting in on the training ground to improve his finishing appear to be paying off after the winger-turned striker found the net for the second match in a row.
After spurning a host of chances in the 3-1 win over Burnley and Europa League defeat to Inter Milan, Southampton were more clinical against City, converting one of their only two shots on target.
Despite losing the possession battle Saints were at their resolute best at the back, restricting City’s star-studded attack to a handful of clear cut chances.
Enforcer Oriol Romeu dominated City’s star-studded midfield and was most pundits’ man of the match.
Jordy Clasie’s up and down start to the season continued as the inconsistent Netherlands international struggled to make much of an impact in the 67 minutes before being substituted.
8 – Rotation has been Puel’s buzzword over the last few weeks and his policy of chopping and changing his line-up appears to be working.
Southampton made six alterations from Thursday’s defeat at the San Siro and despite having 24 hours less recovery than City following their thrashing in Barcelona, they matched the hosts’ energy levels.
Redmond in particular looked fresh after being rested for the trip to Milan due to a minor injury. Puel continued to break in record signing Sofiane Boufal slowly but the Moroccan made a lively cameo after being called off the bench late on.
Player ratings (1-10; 10 = best. Players introduced after 70 minutes get no rating)
GK Fraser Forster, 7 – Busier than he has been in recent weeks and made key saves to deny Ilkay Gundogan and David Silva. Could do nothing to keep out Iheanacho’s fiercely struck equaliser.
DF Cuco Martina, 7 – Continues to deputise for the injured Cedric Soares and is proving a valuable squad player. Kept in-form England winger Raheem Sterling quiet.
DF Jose Fonte, 7 – Again left out in midweek and looked razor sharp against City’s potent attack. Club captain made a couple of vital interceptions.
DF Virgil van Dijk, 8 – Left isolated by the rest of his defence for City’s goal but overall an impressive performance to shackle ace finisher Sergio Aguero.
DF Sam McQueen, 7 – The youngster is growing in stature with every game. It was quite the week for the 21-year-old, having played at both the San Siro and the Etihad.
MF Oriol Romeu, 9 – Would not have looked out of place in City’s midfield. The Spaniard was a one-man blockade in front of the Saints’ back four and is a contender for their player of the season so far.
MF Jordy Clasie, 6 – Failed to grab the game by the scruff of the beck before being replaced by Pierre-Emile Hjobjerg midway through the second half.
MF Steven Davis, 6 – Another player left out of the starting lineup in Milan and as a result had bags of energy to buzz around the middle of the park.
MF Dusan Tadic, 6 – Used by Puel as a weapon to hit City on the counterattack and combined well with Redmond and Charlie Austin as part of a front three when Saints were in possession.
FW Charlie Austin, 6 – Could have done better with one second half chance. Leading scorer led the line well.
FW Nathan Redmond, 8 – Anticipated Stones’ error and showed great composure to round Raul Bravo and find the net to give Saints the lead.
MF Pierre-Emile Hjobjerg, 6 – Must be close to taking Clasie’s spot as a regular Premier League starter.
MF Soufiane Boufal, 6 – The £16million man showed glimpses of his potential with great footwork on the edge of the City penalty area before setting up Austin for a chance.
MF James Ward-Prowse, N/R – No time to make a difference to the outcome.
Alex Crook is ESPN FC’s Southampton blogger. Follow him on Twitter @alex_crook
JAMIE REDKNAPP has named his team of the weekend and there are some interesting selections.
It was an intriguing round of fixtures in the Premier League with Tottenham, Arsenal and Manchester City all surprisingly held to draws by supposedly lesser sides.
The standout result was Chelsea’s 4-0 demolition of Manchester United - and it’s no surprise to see Redknapp choose two Blues stars in his line-up.
CLICK THROUGH THE GALLERY ABOVE TO SEE WHO REDKNAPP HAS CHOSEN THIS WEEK.