(CNN) No sooner had Marine Le Pen taken to the stage to greet her adoring supporters than the rest of the French political system was already moving against her.

As Le Pen spoke of it being the "time to free French people from arrogant elites," those who she had spent her entire campaign scolding were pledging their support to her presidential rival Emmanuel Macron.

If their voters heed the calls to unite behind Macron, this will be his election to lose when he and Le Pen go head-to-head on May 7.

With 97% of the votes counted, the 39-year-old independent centrist is topping the first round of voting with 23.86% to Le Pen's 21.43%

As supporters of his "En Marche" movement celebrated, both Republican rival Francois Fillon and Socialist Benoit Hamon urged their own followers to back Macron.

Their backing would give Macron, who would become the youngest man to lead France since Napoleon, a theoretical majority big enough to Le Pen with an almost impossible task.

Is the result a shock?

In a word, no. French election polls have proved reliable in the past and they were accurate again this time around, with Macron and Le Pen qualifying for the second round as predicted.

JUST WATCHED Macron, Le Pen advance to run-off Replay More Videos ... MUST WATCH Macron, Le Pen advance to run-off 01:40

And three polls have given Macron a 20 point lead over Le Pen going into the runoff.

While many newcomers to French politics may be surprised at the presence of a far-right candidate in the final two, most seasoned observers were expecting such a scenario.

It is not the first time a far-right candidate has progressed to the runoffs. In 2002 , Le Pen's father and founder of the National Front, Jean-Marie Le Pen, made it through to the second round before losing to Jacques Chirac.

The real shock is that this election has seen the complete rejection of the two main parties and Macron's ascent to the top without the backing of a traditional party of his own.

The Republicans and their candidate François Fillon were hampered by a number of scandals which led to calls for him to stand down.

On the left, Benoît Hamon, the Socialist Party candidate, managed to notch up just 6.4% of the vote -- a poor result given his party's president, François Hollande, is currently in power.

For many voters, it seems this election was about the desire for change, and disenchantment with a political class which many feel have left them behind.

France is suffering from high unemployment, a stagnant economy, security worries, and remains bitterly divided. The government has struggled to cope with immigration and integration.

That has played into Le Pen's hands. Many of her supporters feel increasingly alienated by the so-called "political elite."

And it benefits Macron, too. He has projected himself as the country's future,: a young and ambitious man who wants France to remain open and at the heart of Europe.

What are the odds?

Macron's first round result and the endorsements he has received from fellow candidates since place him in a commanding position.

The pollsters have him as a huge favorite -- but there are still a number of potential obstacles which could make his life more difficult.

JUST WATCHED Why these French voters support Macron Replay More Videos ... MUST WATCH Why these French voters support Macron 01:18

One of Macron's chief concerns will be turnout. While his own numbers have remained consistent, he will hope that voters who overlooked him in the first round will heed the call of his rivals to unite behind him.

The only top candidate not to endorse him so far is Jean-Luc Mélenchon, the left-wing firebrand who finished fourth in the first round.

The worry for Macron is that many Mélenchon voters will not bother voting in the second round, insisting on abstaining rather than voting for a centrist candidate.

But as they did in 2002 to prevent her father from assuming power, voters are likely to band together to stop another Le Pen gaining victory.

Dominic Thomas , Professor of French and Francophone Studies at UCLA, says many French people will feel "morally blackmailed" to vote for him in order to prevent Le Pen gaining power.

To combat this, Le Pen will have to persuade floating voters, such as those who backed Fillon in the first round, that she would be a better bet than political novice Macron.

External factors such as a Macron-related scandal or a terror attack could boost her numbers further, but she remains the underdog in this race.

Let battle commence

Le Pen has wasted little time in taking aim at Macron accusing him of being "weak" on Islamist terrorism less than 24 hours after the first round polls closed.

JUST WATCHED Le Pen: France must close mosques Replay More Videos ... MUST WATCH Le Pen: France must close mosques 01:29

The rhetoric between the two is expected to become ever more fierce as May 7 nears.

This is a contest which will be fought on security, immigration, Europe and unemployment -- areas in which the two candidates could scarcely be further apart.

On nearly every single area of policy they disagree -- from Europe through to immigration -- and they will go to a country as divided as the candidates themselves.

"I want to be the president of patriots in the face of a threat from nationalists," Macron told his supporters on Sunday after the results came through.

It is a wish he looks likely to be granted -- unless there is another astonishing sting left in this tumultuous tail.