Moto GP speedster Valentino Rossi is the fifth man to race his way into the semi-finals of our competition to find "The Greatest" sports star in the world today.

The Italian beat off competition from sprint sensation Tyson Gay, basketball scoring machine Kobe Bryant, and the silky skills of Barcelona's Lionel Messi to join Roger Federer, Ronaldinho, Ronnie O'Sullivan and Sebastien Loeb in the last eight.

Rossi picked up 43% of your votes to win the readers poll, and despite only being picked third by our panel of experts - that was enough for victory.

Bryant finished second overall thanks to his second in the experts poll and his third position with the readers; Tyson Gay was the experts top pick but your last selection; while Messi picked up a second (poll) and a fourth (experts).

This week's group sees an intriguing mix of sport starts going up against each other with Michael Phelps (Swimming), Tom Brady (NFL), Thomas Morgenstern (Ski Jumping), and Giba (Volleyball) all in competition.

You may not be familiar with all of these talents, but you can click on the link below the picture to find out all about them.

Then, once you have picked your favourite, why not join thousands of others and vote for your selection via the poll on our homepage?

So what is "The Greatest"?

It is eurosport.yahoo.com's quest to find the greatest sportsman in the world today and we need your help.

We have selected 32 of the greatest athletes in the world to contest the honour and they have been randomly drawn into eight groups of four.

Half of the votes will be decided by the results of our online poll and half by our panel of experts.

And in the great tradition of reality TV shows, in the case of a tie you get the final say.

The winner of each of the eight pools will go into the semi-finals with the winners of those two subsequent groups going into the head-to-head final.

Meet our team of experts:

Gary Imlach - presenter of ITV's coverage of the Tour de France; Channel 4's coverage of the NFL; Eurosport's coverage of the African Nations Cup and winner of the 2005 William Hill Sports Book of the Year award.

Simon Reed - commentated on the last seven Wimbledon Championships for the BBC as well as cricket for Sky Sports plus tennis and ice skating for Eurosport.

Mr Ed - Eurosport-Yahoo's managing editor gets a vote - after all it was his idea.

Their votes for each group have been put in a sealed envelope so not to be influenced by the poll result and paradoxically their decision will not be revealed until each Wednesday morning when the poll ends and the winner is unveiled.

Here's the draw:

Group A: Ronaldinho (Football) (Winner: Poll: 42%; Experts: 2nd) ; Thierry Henry (Football) (Out: Poll 37%; Experts: 4th); Robert Scheidt (Sailing) (Out: Poll: 4%; Experts: 1st) Steve Nash (Basketball) (Out: Poll 16%; Experts 3rd).

Group B: Cristiano Ronaldo (Football) (Out: Poll 56%; Experts: 4th); Ricky Ponting (Cricket) (Out: Poll 6%; Experts 1st); Dan Carter (Rugby) (Out: Poll 5%; Expert 3rd); Ronnie O'Sullivan (Snooker) (Winner: Poll 34%; Experts 2nd)

Group C: Kaka (Football) (Out: Poll 56%; Experts: 3rd); Richie McCaw (Rugby) (Out: Poll 4%; Experts: 4th); Sebastien Loeb (WRC) (Winner : Poll 25%; Experts 1st); Kenenisa Bekele (Athletics) (Out: Poll 15%; Experts 3rd)

Group D: Roger Federer (Tennis) (Winner : Poll 32%; Experts 1st); Floyd Mayweather (Boxing) (Out: Poll 4%; Experts: 4th); Ole Einar Bjoerndalen (Biathlon) (Out: Poll 7%; Experts: 2nd); Ivano Balic (Handball) (Out: Poll 57%; Experts: 3rd)

Group E: Lionel Messi (Football) (Out: Poll 29%; Experts 4th); Valentino Rossi (Moto GP) (Winner: Poll 43%; Experts 3rd); Tyson Gay (Athletics) (Out: Poll 5% Experts 1st); Kobe Bryant (Basketball) (Out: Poll: 23%; Experts 2nd)

Group F: Michael Phelps (Swimming); Thomas Morgenstern (Ski Jumping); Tom Brady (NFL); Giba (Volleyball)

Group G: Tiger Woods (Golf); Jeremy Wariner (Athletics); Chris Hoy (Cycling); Peyton Manning (NFL)

Group H: Fernando Alonso (Formula One); Muttiah Muralitharan (Cricket); Bryan Habana (Rugby); Sidney Crosby (NHL)

It's not about how popular the sports are but more of a reflection on what each individual brings to his respective sport - in terms of domination, entertainment and longevity.

Is Ronaldinho's contribution to football since the millennium worth more than Lionel Messi's value today? Is Ole Einar Bjoerndalen more talented that Kaka?

You decide!

So get voting on the home page poll right now and to help your choice, remember there is a bio of each the Group F contestants available by clicking on the link under the photo.

Eurosport