Undertaker: The Streak 20-0

Early into Undertaker's career, he would smash various jobbers and other established stars in squash matches. This led to a feud with Jimmy "Superfly" Snuka. The match ended when Snuka's attempted springboard maneuver was countered as The Undertaker caught him, and he then hit the Tombstone Piledriver before pinning Snuka.

In mid-1991, Taker would be allying himself with Jake "The Snake" Roberts in his feud with the Ultimate Warrior. During a Saturday Night's Main Event in February 1992, however, Taker turned face and defended Randy Savage's manager and wife, Miss Elizabeth, from Roberts's attack. Two weeks later during a "Funeral Parlor" segment, when berated by Roberts regarding whose side he was on, the Undertaker responded, "Not yours". The feud would culminate in a match at WrestleMania. After delivering his finishing move, the DDT, to The Undertaker for the second time, Jake Roberts went to the outside to attack Undertaker's manager Paul Bearer. The Undertaker then delivered a Tombstone Piledriver to Roberts, before rolling him inside the ring and pinning him.[22]

During the Royal Rumble 1993, Undertaker, who had now been feuding with Harvey Wippleman, began engaging in matches with the wrestlers managed by Wippleman. During the Royal Rumble, Wippleman introduced the Giant Gonzales, who would illegally enter the match to eliminate the Undertaker. This would set up a match at WrestleMania. Giant González was disqualified when he covered The Undertaker's face with a cloth covered in chloroform. This was the only DQ victory in the Undertaker's streak, as all other wins were obtained by pinfall, submission, or casket

Throughout 1994, Undertaker would be sidelined through injury, and during this time, Million Dollar Man, Ted DiBiase Sr., would introduce his own Undertaker, prompting a feud between the two. King Kong Bundy, who was being managed by DiBiase, would step up to face the Undertaker at WrestleMania in 1995. The match, refereed by baseball umpire Larry Young, finished when The Undertaker first bodyslammed and then delivered a flying clothesline to King Kong Bundy before pinning him

On the Royal Rumble of 1996, Undertaker faced then-WWF champion, Bret Hart for the title, but an interference by Diesel costs him the match. As revenge, Taker would then cost Diesel his opportunity for the title at In Your House: Rage in the Cage. The two would settle their feud at WrestleMania, which would be Diesel's final match at the annual event before departing for WCW a month later. Diesel lost to The Undertaker via Tombstone Piledriver.

In 1997, Shawn Michaels vacated the WWF Championship, leaving the new holder to be decided in a four-way elimination match between Undertaker, Bret Hart, Vader and "Stone Cold" Steve Austin. Bret won the match and the title but then lost it to Sid in a match the next night on Monday Night Raw. While Hart and Austin would continue their feud, Undertaker was left free to challenge Sid for the title at WrestleMania. In a match for the WWF World Heavyweight Championship, the finish came when Bret Hart interfered in the match and hit Sid with a steel chair to help The Undertaker take advantage and deliver a Tombstone Piledriver.

At SummerSlam 1997, Undertaker dropped the WWF title to Hart after an accidental attack by Shawn Michaels, setting up a Hell in a Cell match between the two. During the match, Kane was brought by Paul Bearer to cost Taker the match. After being defeated by Michaels at Royal Rumble 1998 in a casket match thanks to Kane, Undertaker would challenge Kane to a match at WrestleMania. After Kane had kicked out of two Tombstone Piledrivers, The Undertaker delivered a third to pick up the win over his (storyline) brother.

Mid-1998 would see the creation of Undertaker's Ministry of Darkness, as it would reignite his pursuit for the WWF title. In his way, however, he opted to switch targets, and aimed to take control of the entire WWF corporation instead. Feuding with The Corporation, Undertaker faced the stable's enforcer, Big Boss Man. The first WrestleMania match to take place inside a Hell in a Cell ended when Undertaker delivered a Tombstone Piledriver to Big Boss Man, who was then hanged from a noose by The Brood. This bout was during the "Ministry of Darkness" era.