There was no middleweight world title on offer for the Bolton man but his slick points win means he can consider himself a strong contender to face unbeaten American Floyd Mayweather in 2015.
Khan has long sought the fight but now, after impressing in Vegas, can offer a genuine case for the match being made.
If he cannot meet Mayweather he is eyeing former stablemate Manny Pacquiao.
Either of those would mean there will be no domestic grudge match with Sheffield’s IBF champion Kell Brook next, but Khan wants to cash in while his stock is high.
“If Mayweather doesn’t happen, Manny Pacquiao is a great name,” he said. “We trained together, there’s a great storyline there.
“With Kell Brook, that fight will always be there but at the moment I want to catch the right guys because how long are they going to be in boxing for? They’re at the top of their game.”
Khan is targeting a May 2 date with Mayweather, who has not lost in 47 fights.
“This puts me in a great position to fight the biggest names of boxing; Mayweather, Pacquiao. That’s where I belong and today (Alexander) was a great statement,” he added.
“Everybody now wants that fight (against Mayweather).
“The public demand, Golden Boy (Khan’s promoters) were saying they want that fight with Mayweather. It’s up to him, the ball is in his court.
“It’s the fight the fans want, why don’t we get it done now? I’m only getting better, I am hitting my peak. I can’t wait to show the world what I have.”
Khan already did that in the early hours of Sunday.
He controlled the fight from the start, using his superior speed to stay ahead of Alexander and out-punching his American opponent who could do nothing to change the rhythm as the night went on.
Khan’s performance was reflected in a comfortable win, with the fight scored 119-109, 118-110, 120-108 – the 30th win of his professional career.
The match-up had been billed as a 50/50 contest, but Khan had other ideas as he controlled the flow of the fight and knocked Alexander off his game.
Wearing his specially-designed shorts encrusted with 24-carat gold, Khan ruled the ring as he was able to have the final word in almost every round. Alexander could not make his jabs count, with Khan’s carefully-timed flurries making much the bigger impact.
Khan was quick and hard with his punches, and Alexander was put on the defensive with his frustration – and that of his corner – clear as the rounds went by.
It was not until the eighth that Alexander landed anything to bring him encouragement, but Khan immediately responded with a big counter-punch.
Alexander, desperate for any momentum, attacked in the 10th but Khan responded with a series of huge blows and Alexander looked resigned to defeat well before the end.
“We worked very hard for this fight,” Khan said.
“I knew I had to make a statement at the 147lbs division against a tough guy in Devon. I think it was one of my best performances because I wasn’t rushing, I was on my feet, up against a very good fighter. I knew not to make any mistakes.”
Before the fight, Mayweather had given the strongest indication yet that he is willing to begin negotiations for a super-fight against Pacquiao in May.
A prospective bout between the two biggest names in the sport has been dogged by promotional and political differences leading many to suggest the biggest fight of a generation may never happen.
But in an interview with Showtime Boxing, Mayweather said: “I would love to fight Manny Pacquiao – we’re trying to make the fight happen.”