Dissecting the short fight, Obi-Wan used the same moves Qui-Gon Jinn did during their battle in The Phantom Menace, tricking Maul into executing the same parry he did before. However, instead of committing the fatal error his master did, Obi-Wan pivoted and hit Maul in the body, killing him.
How was Obi-Wan able to defeat Darth Maul so easily?
The real reason for Obi-Wan's victory, though, may have been that he was the better fighter. While Darth Maul's moves were flashy, Obi-Wan eventually proved himself as one of the best duelists in the galaxy, and his fight with Maul was just the awakening of his skills.
Maul pretty easily had beaten Obi wan and Qui Gon IN A 1v2. He had obi wan defeated but Obi Wan's plot armor made Maul just stand still while Obi wan jumped 20 ft and did 15 flips (evidence for plot armor: Anakin did the same thing in a less difficult circumstance and got sliced).
Like his master, Darth Sidious, better known as Sheev Palpatine, Maul's main weakness was his overconfidence. In Luke Skywalker's confrontation with Palpatine during The Return of the Jedi, he tells the Emperor that his overconfidence is his weakness.
The duel was a brief but fierce skirmish, with Maul gaining the upper hand as soon as he leapt into action. Maul's terrifying combination of agility, anger and ferocity surprised Qui-Gon Jinn, who seemed to tire as the battle went on.
Qui-Gon Jinn & Obi-Wan Kenobi vs Darth Maul [4K HDR] - Star Wars: The Phantom Menace
Could Anakin have beaten Maul?
By the time of Episode 3; Anakin is in his prime, and already one of the Jedi Order's most powerful “masters” (although technically still a knight), just behind Obi-Wan, Windu, and Yoda. Maul wouldn't stand a chance. Anakin stomps.
It's already been shown in the source material… more than once… that Darth Maul is not on Darth Sidious's level. Every time he dueled Sidious as his apprentice (in Legends) he got easily defeated.
Considering his infamy, it's hard to deny that Darth Vader is the more powerful of the two, but his victory over Maul wouldn't come easily. As the Emperor's enforcer, Vader is terrifying.
Regardless, based on the season 7 of The Clone Wars, and the fact that Darth Maul was aware of Anakin Skywalker's future and his role as the Chosen One, it is very likely that Darth Maul indeed feared Darth Vader to some extent, and preferred to avoid a direct confrontation with him, at least, on his own.
Ren was good but Rey was able to beat him every time they fought. However, he wasn't even fully trained and even he would have had a massive problem fighting Maul. Even in his older age, Maul was still way more skilled than anyone Rey faced and that would be the end for her. Maul would just be too much for Rey.
Yoda is extremely wary of the dark side, he knows that it clouds judgment. Maul is a prime example of this. Yoda would easily be able to outmaneuver Darth Maul and then outsmart him.
During the Invasion of Naboo at the climax of The Phantom Menace, Maul first kills Qui-Gon Jinn, then is defeated when Obi-Wan Kenobi bisects him with a shockingly non-fatal blow.
He had killed his master, Qui-Gon Jinn, for which Obi-Wan got his revenge by slicing the Sith in half. But after Maul took yet another person away from him, Obi-Wan absolutely hated Maul. The Jedi Master almost let his rage and anger get the best of him, growing close to the dark side before he rejected it.
The time for revealing the Sith's continued existence to the Jedi came during the Invasion of Naboo, when Darth Maul confronted Jedi Master Qui-Gon Jinn and Padawan Obi-Wan Kenobi. Though he killed Jinn, Maul was, in turn, defeated by Kenobi, who bisected the Sith assassin at the waist.
Star Wars Rebels lead creator Dave Filoni even admitted that Maul and Vader were meant to have a fight, but he felt it would take away from the battle with Ahsoka. But as things stand, Star Wars not only lacks a fight between Vader and Maul, but the two have never even spoken to each other.
Overall, Dooku was far more equipped to become a Sith Master than Maul was. Had he managed to overthrow Palpatine, Dooku would have been able to use his position, combat abilities, and dark side Force powers to take his place on the throne Palpatine had carved.
When Qui-Gon was killed by Darth Maul, Dooku was so saddened that Qui-Gon's death lead to Dooku's transformation into the Sith Lord Darth Tyranus. He would later provoke the memory against Obi-Wan Kenobi, Jinn's apprentice.
Thus, while Qui-Gon was less powerful than the likes of Yoda and Mace Windu, Palpatine feared him more. In the simplest terms, he was a wild card, and with the Sidious executing an intricate decades-long plan to seize power and destroy the Jedi, a wild card was something he just couldn't afford.
Sidious revealed to Maul that he did not intend to kill his former apprentice, as he still had use for Maul; it was Sidious' hope that Maul would lead the Sith to Mother Talzin, Maul's mother and the leader of the Nightsisters, so she could be eliminated as a potential threat to the eventual Sith rule of the galaxy.
Shock: Speaking of fighting style yes Maul could overwhelm Grevious if he had passion to fight and rage but Grevious could adapt his style to counter Maul and overpower him.
