The 24 March 1950 Marciano fought Roland La Starza, winning by split decision.
La Starza may have come closer than any other boxer to defeating Marciano as
a professional. The scoring for the bout was 5–4, 4–5, and 5–5. Marciano won
on a supplemental point system used by New York and Massachusetts at that time.
The scoring system did not award an extra point for a knockdown and Marciano
scored a knockdown in the fight. Referee Watson decided the bout, scoring it
for Marciano. Both boxers were undefeated before the fight, with La Starza's
record at 37–0
Rocco Francis Marchegiano best known as Rocky Marciano was an American
professional boxer who competed from 1947 to 1955, and held the world
heavyweight title from 1952 to 1956. He went undefeated in his career
and defended the title six times, against Jersey Joe Walcott,
Roland La Starza, Ezzard Charles (twice), Don Cockell and Archie Moore.
Known for his relentless fighting style, formidable punching power,
stamina and exceptionally durable chin, Marciano has been included
by boxing historians in lists of the greatest boxers of all time.
He currently ranks #16 in BoxRec ranking of the greatest heavyweight
boxers in history. His knockout-to-win percentage of 87.75 remains
one of the highest in heavyweight boxing history
Marciano scored three more knockouts in a row before rematching Lowry (61–56–10),
who Marciano again defeated by unanimous decision. After that, he scored four
more knockouts and, after a decision over Red Applegate (11–14–2) in late April
1951, he was showcased on national television for the first time, knocking out
Rex Layne (34–1–2) in six rounds on July 12, 1951.
On October 27, 1951, the 28-year-old Marciano took on the 37-year-old Joe Louis.
Coming into the bout, Marciano was a 6½-to-5 underdog. Marciano upset Louis
in what was the latter's last career bout.
After four more wins, including victories over 35-year-old Lee Savold (96–37–3)
and Harry Matthews (81–3–5), Marciano then received an opportunity to win the world title

Although he had one professional fight (against Lee Epperson) on his record,
Marciano began fighting permanently as a professional boxer on July 12, 1948.
That night, he notched a win over Harry Bilizarian (3–6–0). He won his first
16 bouts by knockout, all before the fifth round and nine before the first
round was over. Don Mogard (17–9–1) became the first boxer to last the distance
(full 10 rounds scheduled) with "The Rock", but Marciano won by unanimous decision.
Early in his career, he changed the spelling of his last name Marchegiano.
The ring announcer in Providence, Rhode Island, couldn't pronounce Marchegiano,
so Marciano's handler, Al Weill, suggested they create a pseudonym.
The first suggestion was Rocky Mack, which Marciano rejected. He decided
to go with the more Italian-sounding "Marciano".
Marciano won three more fights by knockout and then he met Ted Lowry (58–48–9).
Marciano kept his winning streak alive, beating Lowry by unanimous decision.
Four more knockout wins then followed, including a five-rounder on December 19, 1949,
with Phil Muscato (56–20–0), an experienced heavyweight from Buffalo, New York,
being the first "name fighter" Marciano faced. Three weeks after that fight,
Marciano beat Carmine Vingo (16–1–0) by a sixth-round knockout in New York
that almost killed Vingo

At 29 years old Marciano faced the World Heavyweight Champion,Jersey Joe Walcott 38 years old
in Philadelphia on September 23, 1952. Walcott dropped Marciano in the first
round and steadily built a points lead. In the 13th, Walcott used his trademark
feint to set up his right hand, but Marciano's "Suzie Q" landed first, a powerful
right hook causing Walcott to slump to his knees with his arm draped over the ropes.
He lay motionless long after he had been counted out and Marciano became the new
World Heavyweight Champion. At the time of the stoppage, Walcott was leading on
all scorecards 8–4, 7–5, and 7–4.
His first defense came a year later a rematch against Walcott,who this time
was knocked out in the first round.
Next, it was Roland La Starza's turn to challenge Marciano. After building a small
lead on the judges' scorecards all the way through the middle rounds, Marciano won
the rematch by a technical knockout in the 11th round.
Then came two consecutive bouts against former World Heavyweight Champion and light
heavyweight legend Ezzard Charles,who became the only man to ever last 15
rounds against Marciano.Marciano won the first fight on points and the second
by an eighth-round knockout. Then, Marciano met British and European Champion Don Cockell.
Marciano knocked him out in the ninth round.
Marciano's last title bout was against 38 year old Archie Moore,on September 21,1955.
The bout was originally scheduled for September 20, but because of hurricane warnings,
it had to be delayed a day. Marciano was knocked down for a four-count in the second
round, but recovered and retained his title with a knockout in round nine.
Marciano announced his retirement on April 27, 1956, aged 32.
He finished his career at 49W-0L