The 2006 Portuguese Grand Prix remains one of the most dramatic races of the MotoGP era.

The 16th and penultimate round of the 2006 world championship, Estoril was action-packed from start to finish - culminating in a thrilling three-way last lap victory battle between Kenny Roberts, Valentino Rossi and Toni Elias.

The significance of what happened in that race has since grown, with many of the landmarks set that day still in place.

Ahead of the 2009 Portuguese Grand Prix, which takes place next weekend, here is a summary of the most significant moments from the 2006 race:

o The motorsport world was stunned when Nicky Hayden got taken out by Repsol Honda team-mate Dani Pedrosa on lap 5 of 28, costing the American the world championship lead he had held since round three in Turkey. The significance of the clash even caught the attention of mainstream media.

o The accident marked Hayden's only DNF of his title winning season.

o Toni Elias took his first and so far only MotoGP win, and with it his first ever premier-class podium. The Spaniard began the last lap in third place, but overtook both Rossi and Roberts into turn one. Rossi then got back in front, but Elias shot past him out of the final turn.

o Elias' victory remains the last time that a satellite rider has won a MotoGP race. Elias, who was riding for Gresini Honda, looked set to lose his seat for 2007 until he took that win.

o The next time a MotoGP race was won by a last lap pass was at Catalunya in 2009 - when Rossi was the winner.

o Second place at Estoril meant Rossi took the title lead for the first (and last) time during the entire 2006 season, having been as far as 51 points behind Hayden after round 11 of 17.

o Rossi lost the race by just 0.002sec to Elias and went on to lose the 2006 world championship by five points when he fell at the Valencia season finale - the same number of points he lost by finishing second to Elias at Estoril.

o Roberts Jr took third, marking the 22nd and final podium of his grand prix career and the last by Team Roberts, which withdrew at the end of 2007.

o Roberts Jr took the lead on the penultimate lap, having thought the race was over one lap early. Unlike Julian Simon at Catalunya 2009, Roberts kept on the throttle when he failed to see a chequered flag.

o KR JR's Estoril performance with the Honda-powered KR211V marked the last time a bike built by a privateer team has led a MotoGP race or taken a MotoGP podium.

o Casey Stoner crashed on lap 2 of the race, bringing down factory Ducati rider Sete Gibernau. Gibernau hit the Australian's LCR Honda, causing the Spaniard to once again injure his collarbone.

o That injury ruled Gibernau out of Valencia, where he was replaced by Troy Bayliss - who sensationally won the race. In a further twist, Stoner took Gibernau's Ducati seat for 2007 and won the world championship.

o Estoril marked Gibernau's last MotoGP start before he announced his retirement. The Spaniard later made an ill-fated return with the Grupo Francisco Hernando team in 2009.

o Estoril 2006 saw the debut of the new Ilmor team, whose rider Garry McCoy was credited with 15th despite being classified four laps down after pitting with electrical problems.

o The Australian and his X3 motorcycle therefore claimed the first ever MotoGP point for an 800cc machine, which officially replaced 990cc bikes from the following year.

CLICK HERE to read's full Estoril 2006 race report and see below for more pictures from the race.