Thatcher was not initially the obvious replacement, but she eventually became the main challenger, promising a fresh start.

The key to his success was consistency, as all about him the main challengers fumbled, stumbled and fell.

United's main challengers to their superiority are now much, much closer to home.

Both are behind their main challengers.

Instead, he embraced the challenge of a mandatory challenger.

Both had been ordered to face mandatory challengers and were stripped of their titles.

Champions, mandatory challengers and hopefuls from all the major organisations are forming a not-so-orderly queue in a bid to fight the division's box-office star.

And so we've seen a parade of potential challengers raise their heads gingerly above the parapet.

Opposition to the prince's rule has been crushed, leaving potential challengers locked up or lying low.

Over the weekend a number of potential challengers broke cover.

At the beginning of the show, six potential challengers would be introduced, and would be selected randomly from that group for each new game.

The person who received the higher vote played against the champion; the other person would be one of the two potential challengers to be voted on for the next game.

He faced a primary challenger, but won with over 70% of the vote.

For the first time since 1994, he drew a primary challenger.

Flake easily defeated his primary challenger.

Each candidate has his own campaign (multiplied by primary challengers).

Ministers hope that it will become a serious challenger to the big banks.

This four-mile winner will not fail for stamina and could be a serious challenger.

However, it continued to attract deposits and increased its lending, cementing its position as one of the most serious challenger banks on the high street.

A serious challenger from the left would have to hit her hard right from the start.

Could become a serious challenger this year.