In August 2001, Singh was brought into New Japan Pro Wrestling by Team 2000 leader, Masahiro Chono, along with another big man, Giant Silva. They were the tallest tag team in pro-wrestling history at an average height of 7 ft 2 in, and a combined weight of 805 lb. The two teamed for the first time at the Tokyo Dome in October, labelled "Club 7" by Chono, and they defeated Yutaka Yoshie, Kenzo Suzuki, Hiroshi Tanahashi and Wataru Inoue in a Handicap Match when Silva pinned Tanahashi and Inoue at the same time. Singh suffered his first loss in a tag match at the Tokyo Dome in January 2002, being cradled by Hiroyoshi Tenzan. He suffered another big tag defeat during March, being pinned by Manabu Nakanishi, and falling to a German suplex hold. His most critical loss came in August at Tokyo Nippon Budokan though, when, after a falling out, he was pinned by Silva in a singles match.
On January 2, 2006, Singh was signed to a contract by WWE and assigned to the Deep South Wrestling developmental territory for training. With Daivari by his side, the un-named Singh debuted on WWE television on the April 7, 2006 episode of SmackDown!, attacking The Undertaker and leaving him out cold during his match with Mark Henry, and thus causing a no-contest. The next week he was introduced as "The Great Khali". He made his in-ring debut on the April 21, 2006 edition of SmackDown! defeating Funaki in a Squash match.
On the May 5, 2006 edition of SmackDown!, Khali signed a contract to face The Undertaker at Judgment Day on May 21, 2006. Later that night, he interrupted a WWE Cruiserweight Championship No. 1 Contender's Triple Threat Match between Super Crazy, Kid Kash and Nunzio, and attacked all three men, as well as Vito.
On the May 12, 2006 edition of SmackDown!, JBL put Khali against Rey Mysterio. Khali had a height advantage of almost 2 feet and a weight advantage of 250 pounds, and gained an easy victory over the World Heavyweight Champion. In his match against The Undertaker at Judgment Day 2006, Khali landed a series of blows on his opponent, and finally defeated The Undertaker with a boot to the head. Khali continued on a rampage for several weeks, winning handicap matches, attacking superstars in a display of power, and mocking the Undertaker's signature pin and victory pose.
On the July 15, 2006 edition of Saturday Night's Main Event, Khali helped the The Big Show beat down the Undertaker with a Double Chokeslam.His replacement was the Big Show. Theodore Long made the announcement after an altercation between Big Show, Undertaker, and Khali backstage. During the course of the Punjabi Prison match at The Great American Bash, Khali did show up at ringside and watched in disbelief as the Undertaker emerged victorious over The Big Show.
On the August 4 episode of Smackdown, Khali was challenged by The Undertaker to a Last Man Standing match at SummerSlam, however, it was announced on the August 11th episode of Smackdown that it will take place on the August 18th edition of Smackdown. This is due to his poor performance at house shows, and WWE's having to edit his actions on Smackdown (which is taped on Tuesday and aired Friday). It has been said that Khali cannot appear on live television.
# SmackDown General Manager Teddy Long replaced The Great Khali with Big Show in the Punjabi Prison Match at the Bash. The Phenom prevailed in the Prison against the ECW Champion.
# On SmackDown, Undertaker was denied a Last Man Standing Match with The Great Khali at SummerSlam. The Phenom came to the ring and gave Khali a massive chokeslam, putting the giant on his back.
