For long she is used to getting her way with even national-level political parties - much bigger than her Trinamool Congress - in negotiations and hard bargaining, but Mamata's maiden foray in playing king-maker on the national stage seems to have backfired.
She now stands virtually isolated, with her bete noire Pranab Mukherjee nominated as a presidential candidate by the ruling United Progressive Alliance, of which Trinamool is itself a constituent.
It was perhaps beyond the imagination of Banerjee, known for her pressure politics, that within only two days of becoming virtually the centrepiece in the national capital as she hopped from one meeting to another - deeply immersed in the negotiations for the presidency - that her dream to become the kingmaker would fizzle out like a hot-air balloon.
Those who have followed Banerjee's political moves over the past two decades would be familiar with the leader's modus operandi - mostly characterised by stubbornness and dogged determination, and less by cool logic and astuteness.
In the 1990s, when she was in the Congress, Banerjee could never match the organisational and manipulative skills of Somen Mitra, and finally broke ranks with the party to form the Trinamool.
As the Trinamool supremo, she supped with the BJP between 1998 and 2006 as an NDA partner.
"During seat adjustments talks or on other matters, there were seldom any two-way negotiations. She would always decide the number of seats to be given to us, and then present it as a fait accompli. She would use her mass support and links with the top BJP leadership to browbeat us," a state BJP president said sometime back.
The Congress had the same experience when it wooed her before the 2001 assembly polls and later in the 2009 Lok Sabha and last year's assembly elections. She always had the last laugh, and the Congress leaders had to be satisfied with whatever she agreed to dole out.
But while Banerjee has almost always come up trumps in her political moves in Bengal - despite her limitations - due to the huge mass following and deep trust of the people, the shortcomings were exposed in Delhi, where Kautilya-like political manoeuvres are a must in inter-party negotiations and where there is little place for personal ego. Unaccustomed to the shrewd political chess board moves in Delhi, where every leader is important, and every leader measures every step after judging what he or she will gain from it, Banerjee came a cropper.
A more astute negotiator would have thought twice before sailing in the same boat with Mulayam Singh Yadav, who has his own reasons to keep the UPA happy.
Having succeeded in making her Trinamool the ruling party in the state from scratch, and having won battles with the UPA on matters like multi-brand retail, pension and land bills, Banerjee probably mistakenly believed she could position herself as a big player in Delhi well in time for the 2014 Lok Sabha polls by seeming to dictate terms to others in the presidential contest.
It now seems that it was due to persuasion from her that Mulayam Singh Wednesday went along with her in announcing three names including that of Prime Minister Manmohan Singh - which surprised all - for the presidency. However, Mulayam made a volte face as soon as Pranab Mukherjee's name was announced.
Banerjee's other objective was to spoil Mukherjee's party - as the two leaders from Bengal have had a long love-hate relationship and she also seemingly did not want a political person from Bengal to occupy the highest office (it now seems her proposing Somnath Chatterjee's name was only a red herring as she pitched only for A.P.J. Abdul Kalam later). She was also cut up with the union finance minister for not granting any financial package for Bengal despite protracted talks.
It may well be that Banerjee thought she would be able to force the Congress, which she perceived to be weak after having browbeaten it time and again in the last three years, into coming round to accept her choice. Little did she calculate that her brash approach in turning down Sonia Gandhi's preferences, and presenting her with her own set of nominees, would steel the party, which took the issue as a prestige fight.
After her Delhi misadventure, Banerjee now returns to her home state facing a hostile state Congress, and with her own image having taken a heavy beating. The Left Front leaders, who have had little to cheer in the past one year, are now laughing their hearts out at "Didi's" flop show in the capital.
Image: Finance Minister and UPA’s Presidential candidate Pranab Mukherjee being presented with bouquets at North Block in New Delhi on Friday.