Third time lucky for Patriots?

The Pats' 1986 defeat was then the biggest in history

As the Super Bowl approaches, BBC Sport Online's Kevin Asseo examines the New England Patriots and the reasons for their surprising success story.

Once again the New England Patriots are in New Orleans to play in the Super Bowl, and once again they are substantial underdogs.

It must feel like déjà vu for the Patriots and their supporters.

Twice before the Patriots have gone to New Orleans for a Super Bowl, and both times as the underdog.

Pats' coach Bill Parcells trudges off in 1997

This time, New England are hoping for a different result.

In 1986, the Patriots were humiliated 46-10 by the Chicago Bears in Super Bowl XX, the most decisive rout in Super Bowl history at the time.

New England fared slightly better in Super Bowl XXXI against the Green Bay Packers, but again went home losers after a 35-21 defeat.

It speaks volumes about the Patriots that, despite the outcomes, those Super Bowl appearances are probably the two proudest moments in franchise history.

Because, in 41 seasons of existence, that is as close as they have ever come to winning a league championship.

The Patriots' unexpected success this season has been built on the foundation of a strong, opportunistic defence and a smart, balanced offence that has continually caught opponents off guard.

Physical play

Head coach Bill Belichick has always had a reputation as a defensive mastermind, and in his two years with the Patriots he has not disappointed.

Although the New England defence yielded plenty of yards this season, it has buckled down where it matters most - close to the end zone.

The Patriots allowed opponents an average of 17.0 points per game, sixth best in the NFL.

Cornerback Ty Law and safety Lawyer Milloy set the tone for a New England secondary that loves physical play, which is essential in slowing down the speedy Rams' receivers.

Tom Brady celebrates his TD against the Raiders

The Patriots' linebackers, led by veterans Bryan Cox and Ted Johnson, have been another strength.

They were superb in shutting down Pittsburgh's much-hyped running game in last week's AFC Championship game.

On offence, the story of the year for New England has been the play of second-year quarterback Tom Brady.

After taking over from the injured Drew Bledsoe in week two, Brady has impressed with his poise and consistency while guiding his team to a 13-3 record in his games as a starter.

But how the young quarterback handles the pressure of being on American sport's biggest stage remains to be seen, and the Rams will surely do all they can to rattle him.

Of course, it does not hurt to have Bledsoe, a $100m (£71m) backup, waiting in the wings if Brady cannot perform adequately.

Another unexpected strength for the Patriots' offence has been the performance of running back Antowain Smith.

Antowain Smith has given the Patriots a new option

Signed in the off-season to bolster a lacklustre running attack, Smith has done just that, gaining over 1,000 yards. He has also complemented the passing game.

And do not forget wide receiver Troy Brown, the unsung hero for the Patriots.

He has had a wonderful year both on offence and special teams, as he showed once again with an epic all-around performance against Pittsburgh last week.

Though the Patriots' offence has its share of stars, it is not a point-scoring machine like the Rams' and will need to take advantage of every opportunity it gets to keep up with St Louis.

Belichick, the defensive guru, faces the biggest challenge of his career in coming up with a way to slow down the Rams' high-powered offence.

If he can do that, perhaps Tom Brady and the Patriots can finish their extraordinary season with the biggest surprise of all - a Super Bowl victory.