As is Saesee Tiin.
"In addition to being a skilled, courageous master of the lightsaber, he was also a very capable starfighter pilot."
-Source: starwars.com databanks
"Mace manages to assemble a trio of celebrated swordmasters to assist him in arresting Palpatine."
-Source: The Complete Visual Dictionary
'Now Obi-Wan did face him. "Palpatine faced Mace and Agen and Kit and Saesee-four of the greatest swordsmen our Order has ever produced. By himself."'
-Source: Revenge of the Sith
He indeed has, but I wouldn't be so confident that he has Tiin beat here. Strength is, after all, Saesee's primary attribute.
Saesee: "My strength has never failed me."
Mace: "You can't smash your way through the entire droid army..."
Saesee: "Watch me."
-Taken from Heavy Metal Jedi
Feats originating from comic strips or clips from the Star Wars: Clone Wars miniseries are-for the sake of debate-not permitted because of the material's exaggerated portrayal of Jedi's abilities. In spite of this fact, I would like to point out that in all of his portrayals in this series he demonstrates using his immense physical strength to overwhelm his assailants as his go-to tactic, ranging from smashing droids to stopping moving speeders. So take that as you will, moving on.
Saesee is able to comfortably deflect fire from a dozen armed pirates while holding a grown man under his arm:
"The two judicials who had fought beside Tiin were wounded. The Iktotchi carried one of them under his left arm, while he continued to divert bolts with the lightsaber clutched in his right hand."
-Source: Cloak of Deception
And here, most impressively, Mace heavily implies that between them Saesee is stronger, and he the faster:
Mace: "Don't worry. We still have your strength. And my speed."
-Taken from Heavy Metal Jedi
This is especially meaningful considering Mace's own feats of strength are more than impressive.
http://static.comicvine.com/uploads/ignore_jpg_scale_super/11113/111137054/4058450-hghfhfgh.gif
-Source: TCW S6 (Credit to Marco)
While this is true to a point, I would like to make it clear that Maul is a decisive tier ahead of Qui-Gon in dueling skill.
For starters, let's take a look at their first fight. Maul's performance is hindered by a broken ankle throwing off his balance, and while Qui-Gon is initially able to match him, he is regardless on the verge of defeat when he is rescued:
"It is because of my wound. It has slowed me down somewhat. It is almost imperceptible, but it is there. The Jedi has an advantage. I am not at my best. This realization sends more rage pumping into my body. I am angry at myself, but I use the anger to fuel the dark side. I feel the Force come from the Jedi and I send it back to him, showing him that I, too, have a connection, and it is stronger than his. I launch a furious counterattack. I feel the Jedi is beginning to tire, and triumph rises like a red mist before my eyes. I gain the advantage. I am winning. I will defeat him."
-----
"I feel a savage pleasure course through me. His weakness feeds my power. I drive him back, spin around when he parries, drive him back again."
-Source: Episode I Journal: Darth Maul
Taking a look at their second battle, the combined skills of Qui-Gon and Obi-Wan are no match. Maul easily repels their attacks and only feigns being pressed throughout the duel:
"Rapidly spinning his lightsaber blade, he anticipated their moves with ease. Having expected a greater challenge from Qui-Gon and Obi-Wan, he felt even more disgusted by them."
-----
"Maul leered again at Qui-Gon. You think you're driving me back. You have no idea that I'm in control. You don't know where I'm taking you. Maul sensed the laser doors opening behind him. Qui-Gon was unrelenting in his ongoing attack, but Maul parried every blow. Qui-Gon swung at Maul's legs, but the blade swept under his feet as Maul jumped backward. Maul continued moving back, leading Qui-Gon into the hallway. They passed the first four security barriers before the doors activated and shut."
-Source: The Wrath of Darth Maul (Credit to ILS)
"Obi-Wan brought youth and stamina to the combat, but he had fought in only a few contests and was not battle hardened. Together, they were able to hold their own against the Sith Lord, but their efforts at attack, at assuming the offensive against this dangerous adversary, were woefully inadequate."
-Source: The Phantom Menace novelization
After his death:
"He had been more than the equal of the Jedi Knights he had faced and should have been able to defeat them easily."
Source: The Phantom Menace novelization
I'm not sure how this is relevant here. We're discussing Qui-Gon as we've seen him--that is, as he appeared in The Phantom Menace.
You claim it's impressive that Qui-Gon can participate in an extended duel despite his demanding fighting style and increasing age. As admirable as that may be, the fact that he is growing old and does adopt a highly demanding lightsaber form is an inherent disadvantage--In both of his duels with Maul, these two facts have proven to be his downfall. It could be said for him that he can stave off his fatigue well, but I find it to be a highly unlikely notion that Qui-Gon is going to outlast Tiin in this contest.
You've spoken your peace in regards to Qui-Gon's strengths, allow me to shed some light on Saesee's. In addition to being a master swordsman, he is one of the Order's greatest masters of the Force:
"Saesee's flying practice also helped to hone his Force abilities. By the time he arrived at the Jedi Temple, he was already adept at channeling his Force connection. As he progressed in the Order, he was acknowledged as having one of the strongest Force abilities of all the Jedi."
Source: The Official Star Wars Fact File #114 (Credit to Silver)
You've already acknowledged Saesee's telekinetic ability in the past, so with that in mind, let's move on to one of Saesee's greatest, but less acknowledged talents with the Force: Telepathy. In the past this ability has been underappreciated due to the belief that it lacks combat applications, but I would like to dismiss this notion. Here, Saesee describes some of the advantages of telepaths in the Great Holocron:
"In combat, telepaths do have a distinct edge. Even if one fights by instinct and reflex, most cannot stop themselves from emitting monosyllabic thoughts that project their next movement. During my training bouts at the Jedi Temple, my opponents unwittingly revealed their every move, allowing me that crucial fraction of a moment that enabled me to be the one who would remain standing."
-----
"He showed me how to use the Force to isolate my own brain waves, intercept stray thoughts, and screen dozens of minds at once. How to whisper across space, yell without noise, keep secrets, and sift through layer of lies and buried memories to uncover the truth."
Source: Jedi vs Sith: The Essential Guide to the Force (Credit to Silver)
Here, in what may be the most relevant demonstration of his telepathic abilities, Saesee is able to probe Qui-Gon's mind and detect him lying to Yaddle:
'"I'm not worried, Masters," Obi-Wan said good-naturedly. "I'm only thinking forward." He waited for Qui-Gon to offer some piece of wisdom regarding the living Force, but for once his Master kept silent.
"Right you are to think forward, Padawan," Yaddle told him. "Deal lightly with matters of consequence, and decisively with those of little consequence. Difficult it is to face a crisis and solve it gently, if not resolved beforehand you are, for uncertainty will impede your efforts. When comes the time, thinking forward allows you to deal lightly."
Her big eyes shifted to favor Qui-Gon. "Agree do you, Qui-Gon?"
He bowed his head. "As you say, Master."
Diagonally across the table from Yaddle, Saesee Tiin glanced up and smiled, as if reading Qui-Gon's thoughts.'
-Source: Cloak of Deception
To sum things up, in regards to comparison with Qui-Gon, Saesee Tiin is comparably skilled, stronger, a more powerful telekinetic, and his ability to telepathically read his opponent's moves before they happen gives him a distinct advantage. IMO He should be able to bag 5 or 6 wins out of 10, here.
Phew, that took longer than I had expected. Sorry for making it so long, I may have gotten a little carried away. G'luck.
