* Williams U.S. Open win streak at 22 matches
* Diatchenko quits with foot problem (Adds quotes, detail)
By Steve Keating
NEW YORK, Aug 31 (Reuters) - Serena Williams began her final push towards a calendar year Grand Slam in devastating fashion on Monday by pounding Vitalia Diatchenko 6-0 2-0 before the overwhelmed Russian waved the white flag and retired.
Following a Broadway style opening ceremony complete with orchestra and choir, Williams stepped onto centre court under a spotlight to loud applause from the New York crowd just seven matches from her goal.
The six-time U.S. Open champ exited Arthur Ashe Stadium just 30 minutes later to more applause and with her target reduced to six more wins to join the exclusive club of calendar Grand Slam winners Maureen Connolly, Margaret Court and Steffi Graf.
"It's great to be here in Arthur Ashe Stadium, to be American, just to be on this journey in my life," Williams, who already has the Wimbledon and Australian and French Open titles in the bag, told reporters.
"It's kind of awesome that this is the last grand slam of the year, because if it were in a different country I think I would still love it but it's not the same as being an American playing in New York, playing for that ultimate goal."
Standing across from the world number one for the first time, Diatchenko appeared frozen in fear as Williams won 32 points to just five by the Russian.
In just seven minutes, the 21-times grand slam singles champion and defending U.S. Open title holder was 3-0 up against her 86th ranked opponent.
A shaken Diatchenko called for the trainer to look at her left foot after going 5-0 down in the first set, and after Williams wrapped it up the Russian left the court for more treatment.
With Williams taking a 2-0 lead in the second, Diatchenko signalled she had suffered enough and after a brief chat with the chair umpire walked over to shake her opponent's hand.
"It was definitely different and bizarre but at the same time I was still focused," said Williams, who has only lost two matches this season. "I kept thinking, just stay focused; don't lose it. You never know what can happen."
The victory stretched Williams' grand slam winning streak to 29 matches. She is now unbeaten at the U.S. Open in 22 matches going back to a loss to Sam Stosur in 2011. (Editing by Peter Rutherford)