LAS VEGAS — RingTV.com will have live, round-by-round updates of tonight's welterweight clash of former titleholders during which Amir Khan scored three knockdowns on the way to a unanimous decision over southpaw Luis Collazo at the MGM Grand on Showtime Pay Per View.

Khan (29-3, 19 knockouts) dropped Collazo (35-6, 18 KOs) once in the fourth and twice in the 10th, winning by scores of 117-106 on the card of judge Jerry Roth and 119-104 of those of Cathy Leonard and Adalaide Byrd.

Khan had been out of the ring for more than a year, last being in action for a unanimous decision over two-time lightweight titleholder Julio Diaz on April 27 of last year. Khan had relatively struggled over the course of his previous six fights, going 4-2 with two knockouts.

In the 33-year-old Collazo, Khan made his 147-pound debut against a career welterweight who had gone 6-1 with four knockout victories in his previous seven fights.

Collazo is 4-0 with two stoppage wins since falling by 10-round unanimous decision to Freddy Hernandez, who dropped him in the eighth round in October 2011. Collazo had last been in the ring for a second-round knockout of ex-beltholder Victor Ortiz, a fellow left-hander, in January.

Showtime’s Pay Per View broadcast begins at 9 p.m ET/6 p.m. PT.

Khan vs. Collazo

Click here for who wins Amir Khan versus Luis Collazo

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Referee: Vic Drakulich

Judges: Adalaide Byrd 119-104, Jerry Roth 117-106, Cathy Leonard 119-104 all for Khan

RINGTV.COM HAS IT FOR KHAN, 117-106

Round 1:  Khan prayed in his corner with his back to the ring prior to the bell. Fighters are at ring center, Collazo circling out of his southpaw stance. Khan aggressively jabs early. Collazo stands his ground. Long right by Khan misses. Jab to the body by Khan. Two right hands by Khan, the first of which lands. Another right by Khan lands. Two left crosses from Collazo, one of which is blocked. Collazo stalking. Counter right by Khan. Two left hands by Khan. Khan fires three rights to the body during a clinch. Khan, 10-9.

Round 2: Khan fires a right and then two lefts behind it early. Khan's busier during a clinch, getting off first. Collazo, hands down, continues to stalk. Right to the body by the elusive Khan. Solid right hand pops back Collazo's head. Right to the body and left also both by Khan. Clinch. They trade uppercuts, a right by Khan, left by Collazo. Khan's speed is the difference so far. Double-jab and rto right hands by Khan. Solid left hook by Khan. Jab to the body by Khan. Jab and right hand by Khan. Collazo clearly wants to land a big punch. Jab and right by Khan. Khan blocks three solid attempts by Collazo along the ropes, but Collazo continues to press. Khan, 10-9; Khan, 20-18.

Round 3: More of the same from Khan to start the third — lateral movement and speed off the jab. Lead right hand to the head by Khan. Three-punch combination by Khan. Clinch. Collazo clearly is trying to walk through Khan's punches for the big shot. Solid right hand by Collazo, but he still is getting out-hustled. If Khan can keep this up, he will have an easy night. But how big of an IF is that? Nice right hand by Khan prior to the bell. Khan, 10-9; Khan, 30-27.

Round 4:  Same thing to strat the fourth, but COLLAZO GOES DOWN FROM WHAT APPEARS TO BE A SNEAKY STRAIGHT RIGHT ON THE INSIDE SWIVEL'S COLLAZO'S HEAD. HE'S UP. He does not appear to be badly hurt, but Khan, nevertheless, continues to remain on his bicycle. Solid right hand by Khan. Another right over the jab by Khan. Another solid jab and a right by Khan. Solid right hands by Collazo. Collazo's loading up, but missing often. Khan's remaining disciplined behind his jab and covering well when on the ropes. Right by Khan. Khan, 10-8; Khan, 40-35.

Round 5: Khan resumes boxing, jabbing and moving. Collazo, hands at his side, daring him to stand and trade. Collazo fires three lefts that are blocked during a clinch. Khan's busier during a clinch. Right, left, right all from a distance by Khan. Left hook on the inside by Khan. Solid right by Khan. Again, speed is the difference for Khan. Triple jab and right hand by Khan. Two hard right crosses and a left by Khan. Khan, 10-9; Khan, 50-44.

Round 6: Khan's jab and movement continue to befuddle Collazo. Blistering five punch combination by Khan, who moves away. Two left hands by Collazo, three right hands by Khan. So far, good discipline by Khan. Right over the top by Khan. Collazo, so far, a few steps too slow. Jab and right by Khan, who, so far, covers up well when on the ropes. Pawing jab and a right by Khan. Lead right by Khan. Two more lead rights and a jab by Khan. Collazo's just following. Solid right by Khan prior to the bell. Khan, 10-9; Khan, 60-53.

Round 7:  Six unanswered jabs open the round for Khan, followed by a right. No answer from Collazo, who still follows. Jab and right cross by Khan. Right to the body by Collazo. Solid right by Khan. Two more rights by Khan penetrate Collazo's guard. Lone right by Collazo and a left. Right by Khan. Clinch. Right to the body, left to the head, right to the body for Khan. Right by Collazo after a left is blocked. They trade left hands. Two rights by Khan. Low blow left hand by Collazo. Lead right by Khan, who remains elusive. Khan, 10-9; Khan, 70-62.

Round 8: It appears that Khan's movement has led to frustration and a low blow by Collazo, who is penalized a point by referee Vic Drakulich. More movement and jabs by Khan, who takes a right to the body along the ropes. Collazo's bleeding from a cut over his left eye as well as from the mouth. They trade right hands, but Collazo's left hand shakes Khan, who mugs as if to say he's not hurt. Another left to the chest by Collazo. Khan penalized a point for holding. Khan gets off a right, left, right combination. Collazo, 9-8; Khan, 78-71.

Round 9:  Collazo's motivated for the big punch, yet again. Khan's firing the right an clinching. Collazo pounding at the body when he gets close. Right hand inside by Khan. Four-punch combination by Collazo, left, right, left, right. Collazo hammers away at a covered up Khan. Left gets through Khan's guard. Not much on Khan's punches. Two lead lefts by Collazo, who is trying to hurt Khan. Right by Collazo. Left by Collazo. Another right by Collazo as Khan moves away. Lead right by Khan. Crowd chanting "Louie." Five punch combination by Collazo. Collazo, 10-9; Khan, 87-81.

Round 10:  Lead right, left, right by Khan. Right by Khan that grazes. Right by Khan sprays sweat from Collazo's head. Another grazing right by the busy Khan, followed by a jab. Two jabs by Collazo. Left and right by Khan. Triple-jab by Khan. Jab by Collazo. Left to the body by Khan, right, left and another left to the body as Collazo retreats to the ropes. Right to the head by Khan. COLLAZO'S DOWN FROM A RIGHT TO THE BODY AND A LEFT TO THE HEAD!!! HE'S UP AT AROUND THE COUNT OF EIGHT. Collazo looks away to complain and gets ROCKED BY ANOTHER PUNCH, A LEFT HOOK, AND GOES DOWN. He's up, but getting hammered along the ropes. Khan, 10-7; Khan, 97-88.

Round 11:  Khan's back to pounding way behind his jab and right hands. Collazo lands to the body twice. Khan retreats and goes back to boxing. Left hook and right hand by Khan. Khan's discipline is showing for one of the rare times in his career. He's giving Collazo a boxing lesson. Right uppercut by Collazo. Right to the body by Khan. Another right to the body by Khan and one to the head. Khan, 10-9; Khan, 107-97.

Round 12: Khan's got some swelling over his left eye. Left to the groin by Collazo lifts Khan off the canvas. Right on his baby maker. He takes a break on his knees. Khan's back to boxing, lead rights and jabs. Right to the head and left to the body for Khan. Khan appears to be bleeding from a cut on the bridge of his nose. Jab by Khan. Another jab by Khan. Clinch. Left to the body and head by Khan. Jab by Khan. Khan has out-hustled and out-speeded and out-smarted Collazo. Good effort in his 147-pound debut. Two clean jabs by Khan. Jab, jab and right by Khan, who thrusts his hands skyward in joy. Khan, 10-9; Khan, 117-106.

RINGTV.COM HAS IT FOR KHAN, 117-106