Pomar v.s. Petrosian, 1970

Position after 14. g4

"The opening is fairly typical of Petrosian, in that he has been deliberately provocative. Even by modern standards, his set-up looks a bit bizarre. It seems that you could give Black several moves and he wouldn't know what to do with them. But Petrosian is unfazed."

14... Rb8! 15 Rhe1 Rb7!

"There is an irony here, placing a rook vis-a-vis White's g2-bishop. But Black's last two moves are the essence of prophylaxis. As Soltis comments: "Look around for an immediate threat to Black's second rank and you won't find it. But Black is thinking about the near future." This use of the second rank for defensive purposes has been mentioned elsewhere in the book and it also occurred in the last example. Here the rook not only defends d7, but is ready to swing into the centre or to the kingside when appropriate. White now jumps at the chance to activate his pieces at the mere cost of giving his opponent an extra pawn which is isolated and doubled. But due to the prophylactic nature of Black's position, this also activates [Petrosian's] pieces, and in particular that rook."

16 e5?! fxe5 17 Ng5 o-o 18 Nd5 Nxg5 19 Bxg5 Be8! 20 Bh6 e6 21. Bxg7 Rxg7

"Black's last three moves prepared this!"

22 Nc3 Nd5 23 Rxe5 Rgf7

"Black is winning, the f-file pressure is too strong."

24 Ne4? Qc7 25 Rg5 Rf4! 26 Qd3 h6 27 Nd6 hxg5 28 Nxe8 Rxe8 29 Qxg6+ Kf8 30 Qxg5 Qh7+

There were a fair number of short draws before Petrosian won the title as well. Here is an example from his early days as a top player:

Hard to imagine holding this view, come to the only player during the period 1951-1975 to win a match outright against his challenger.

For the uninitiated:

Botvinnik, 1951: managed to draw vs Bronstein;

In 1954, again 12-12;

In '57, Smyslov won as challenger, then lost as champeen the next year;

Botvinnik again lost as champ in 1960 and the next rematch in 1961;

Last go at it for the Patriarch in '63--he lost decisively to Iron Tigran;

Success for the titleholder came in 1966, with Petrosian winning by the odd point, before a resurgent Spassky defeated him three years on.

Surely in general terms there can be no such thing. However if we go along with this idea and hold a poll I'm pretty sure poor Euwe will come out on top even though he held the title longer than Smyslov and Tal.

The Draws.
I've read many times that Petrosian played like a sleeping bear. If you woke him up you were in big trouble. A die hard Petrosian fan (count me out) could make a case that it was not Petrosian's fault for these draws, it was his opponents for being to scared to tackle head-on.

So whilst a Tal and Fischer were more competitive in the quest for maximising win probability however the methods, Petrosian was more interested in the objective truth of things, because he liked "order" and the scientific objective angle on chess.