The defender’s late header ended the Ewood Park outfit's 11-year spell in the top flight of English football and sealed his side's status for another year
The visitors largely dominated the match but Blackburn were frustrated not to be awarded a second-half penalty for a foul on Junior Hoilett.
Fans invaded the pitch at the final whistle in further opposition to the club’s management and owners on a night of protest at Ewood Park.
With Rovers knowing that only a win would suffice, Steve Kean made two changes to the side which lost 2-0 at Tottenham. Martin Olsson replaced his brother Marcus at left back, while striker Anthony Modeste came in for Mauro Formica in a more attacking line-up.
Unsurprisingly, Wigan were unchanged from their incredible 4-0 win over Newcastle and knew that a point would all but secure their Premier League survival.
It was a frantic start from the hosts as the cries rang out from the Ewood Park faithful venting their anger towards both manager Kean and the club’s owners.
The game's first opportunity went to the visitors, David Dunn had possession stolen from him by Shaun Maloney who fed in Victor Moses but his effort flew well over the bar.
In the strangest of twists the game was paused when a chicken was let loose onto the pitch; a strong visual protest from the Rovers fans to match the chorus of boos.
Wigan continued to press and Paul Robinson produced a smart save to deny Franco Di Santo. Moses provided the assist but Robinson got down to his left and Gael Givet cleared the danger.
However, Blackburn responded well and created a chance of their own soon after. Yakubu’s knockdown fell to Modeste outside the box, but his sliced volley went narrowly over.
With Ben Watson pulling the strings in midfield, Wigan continued to dominate the home side, who began to sit deeper and deeper. The pace of Moses again had Blackburn reeling as Scott Dann failed to stop the winger coasting into the area before he shot straight at Robinson from a tight angle.
The visitors' frustrations continued as Maloney sent a free-kick deep to the far post which Gary Caldwell nodded back across goal. Unfortunately for the Latics, Watson inadvertently took the ball from Moses in an attempt to control.
Wigan were once again wasteful shortly before half-time when Moses made a mess of a free header, nodding it back to where it came from. Di Santo had whipped in an inch perfect cross which Dann misjudged but Moses could not capitalise.
Blackburn were equally wasteful with their ventures into the Wigan half though. A free-kick on the right-hand side was hit hard and wide by Morten Gamst Pedersen and out of reach of the large contingent of his team-mates who had crowded the area.
After the break Rovers began the brighter and Pedersen’s rasping shot from the left went just over after a fantastic long ball from substitute Radosav Petrovic.
Wigan were then soon on the front foot but shots from Jean Beausejour and James McCarthy did not trouble Robinson.
Rovers’ best chance came minutes later; Dann towered above his marker to head across to Yakubu but the Nigerian could not keep his balance and scuffed a shot which was easily blocked.
The match’s most controversial moment came on the hour mark as another header back across goal caused a scramble in the area. As Emmerson Boyce went to clear he connected only with Junior Hoilett, but referee Mark Clattenburg waved away the appeals.
Wigan were then denied a penalty kick when Moses sped past Bradley Orr but Clattenburg adjudged Moses to have dived after he passed Pedersen in the Blackburn area.
With ten minutes to go Blackburn brought on David Goodwillie for right-back Orr as relegation crept ever closer with the score still at 0-0.
As soon as Rovers had made the substitution they almost fell behind, Moses’s shot was palmed out by Robinson straight to McCarthy who couldn’t provide a lethal touch.
With the away side well on top in the closing minutes it was no surprise when Wigan did eventually take the lead. Alcaraz climbed highest at the back post to head a corner kick at goal which was too hot for Robinson as Rovers’ Premier League status was taken away from them.
Commentaries, Stats, Player Ratings and much more,
Visit Goal.com Live Scores!