The Dagenham lightweight floored the WBC champion in the fifth but by the time Mitchell was sent to the canvas in the tenth his left eye was severely swollen and there could be no complaints with the referee stopping the bout.
Roared on by his fans in the O2 Arena, Mitchell – who had previously lost world title shots to Ricky Burns and Michael Katsidis – showed his intent with a left hook in the first but felt Linares??? power when the Venezuelan landed two heavy rights.
Both men adopted a more cautious approach in the second, but Mitchell sealed the third with a good left to the body.
However, a clash of heads in the fourth left Linares cut on the side of his head ??? and, crucially, Mitchell with a gash above his left eye.
The Essex fighter then sent the crowd wild with a short right which put Linares on his backside in the fifth. Mitchell pursued his man to try to finish the contest and, although Linares recovered well, the champion sustained another body shot, with the 30-year-old well on top.
Good combinations followed in the sixth, with Mitchell picking his moments to expose Linares, and by the seventh the title holder was regularly missing with hooping rights, while the Englishman fired in accurate body shots.
A right from Linares drew blood from Mitchell???s nose in the eighth, though, and the challenger???s left eye ??? which had almost swollen shut – was now noticeably causing him problems.
Linares sustained his pressure, unloading solid combinations up top and pinning Mitchell back on the ropes.
Linares remained on the front foot through the ninth, and stiffened Mitchell???s legs at the start of the tenth with a crisp right. Incredibly, the brusied and blooded Mitchell fought his way off the ropes and back to the centre of the ring ??? to the delight of the crowd.
But Linares unloaded yet more flurries to Mitchell???s head and the challenger was forced to the canvas. He got to his feet to fight on ??? but was in no state to continue.??