Not much from Amir Khan tonight to worry Kell Brook
The Bolton welterweight, in his second fight since returning to the ring after a two-year absence, was knocked to the floor in the final seconds of the second round.
Colombian-born Vargas, 29, had already been put down himself when he stunned Khan and the capacity crowd.
But, with potential next opponent Kell Brook watching at ringside, Khan recovered on his stool, came out and floored Vargas again.
The 31-year-old was unable to finish the job there and then, though, and eventually had to settle for a unanimous points victory from what was at times a gruelling battle.
But it was not a performance which will give the likes Brook or Manny Pacquiao too many sleepless nights.
Brook said later he would not have let Khan off the hook, as Vargas had.