Italy’s Valentino Rossi renewed his attack on Spain’s Marc Marquez after Sunday’s MotoGP title defeat at Valencia’s 18th and final round of the series.

Rossi saw a seven point lead over Yamaha team-mate Jorge Lorenzo evaporate when a fourth place finish – from the back of the grid – was combined with victory for Lorenzo, who celebrated winning his fifth world title and third in the premier MotoGP class

Marquez shadowed fellow Spaniard Lorenzo throughout Sunday’s race, riding hard to stay with the Yamaha rider but never making a pass. The pair were caught by Marquez’ Repsol Honda team-mate Dani Pedrosa in the closing stages.

For Rossi the fact Marquez didn’t overtake was proof he “wanted to finish his work” and “try to protect Lorenzo”.

Rossi had been sent to the back at Valencia for causing a clash with Marquez at Sepang – a few days after Rossi sensationally accused the Spaniard of trying to help Lorenzo in the Phillip Island race.

The Italian cut swiftly through the field at Valencia, but reached his realistic limit of fourth place by lap 13 of 30. With Lorenzo, Marquez and Pedrosa long gone – Rossi’s championship hopes now depended on both Repsol Honda riders beating Lorenzo.

That didn’t happen and Rossi, never headed in the 2015 championship points until Valencia, saw a tenth world title slip away by just five points.

“This is the final of the championship that I personally, and also I think a lot of people, don’t want to see because it was a great season, with a great battle with Marquez and especially Lorenzo,” said Rossi, speaking in front of a mixed audience of media, Movistar Yamaha guests and VR46 fan clubs members – some of whom were in tears.

“I think that this championship had the potential to become one of the best of the last years because the battle with Jorge can arrive at the last point at the last race.

“But unfortunately at the last three races something changed and something happened that nobody expected. First of all me, but also a lot of people. That is Marc Marquez decided to protect Lorenzo to help him win the championship.

“So the problem started at Phillip Island and became worse and worse. We arrived in Malaysia where unfortunately we touch and Marquez crash. Then I learn on Thursday that I had to start last here – I knew already my championship was finished because I was sure Marquez wanted to finish his work and try to protect Lorenzo also in the last race.

“I said this already Thursday and it happened exactly as I expected.

“Today the race was quite embarrassing. The last lap I think was quite bad for all the sport, because something happened that never happen before and I’m not desperate [at losing the title] because I think I play my cards in the best way, but I’m very sad with this finish.

“I was ready to lose the championship to Jorge, who is always very fast, but this way for me is not fair.”

Marquez denies ever assisting Lorenzo, pointing out he took five points from the Yamaha rider by passing him for victory on the last lap at Phillip Island and insisting there was nothing unusual in the Sepang showdown with Rossi – until the #46 made his extreme block pass.

And Valencia? Marquez said if he was trying to help Lorenzo he would have dropped five-seconds behind, not been applying constant pressure from a few bike lengths. The #93 added that a late attack for the lead never came because he lost time when briefly passed by Pedrosa. The race finished with Marquez 0.263s from Lorenzo and Pedrosa 0.654s from victory.

Rossi was asked to respond to Marquez’s explanation.

“For me if you check the races of Marc Marquez in the last two years you know he always tries to overtake and minimum on the last lap. So the question is, why Marc Marquez never tried to overtake Jorge Lorenzo and never tried to make one attempt on the last lap?” Rossi replied.

“The situation became very embarrassing for Pedrosa, because Pedrosa was far [behind] and in the last laps he recovered two-seconds, which means that is the pace of Jorge and Marquez just waited.

“And for me, he [Marquez] liked that he helped Lorenzo and after when he take off the helmet he is just saying it is not true. But for me, he knows I will look at the television and it is clear that he helped Lorenzo, for me he is happy.”

Rossi also turned his sights on Honda: “For me the position of Honda is very strange. I don’t know how a manufacturer can be agreed that one of its riders make the Yamaha win and try to fight just with his team-mate [Pedrosa]. This is very strange. But sincerely I don’t understand.”

Paddock opinion remains divided as to whether Marquez could have made a pass, or was already on the limit.

Either way the allegations mean that the 2015 season, in which Rossi’s title challenge at the age of 36 captivated the motorsport world, ends on something of a sour note.

The Italian won seven championships between 2001 and 2009, but a downward spiral began with a broken leg in 2010, followed by two winless seasons at Ducati.

Then came a winning return to Yamaha, but a bittersweet 2013 saw him blown away by Lorenzo. A shock change of crew chief underlined that Rossi wasn’t content to make up the numbers and he turned the tables on Lorenzo last year, albeit a distant second behind the all-conquering Marquez.

While Marquez and Lorenzo faltered in the early stages of this season, Rossi used all of his experience to wring out 12 successive podiums, including four wins. His rostrum tally would reach 15 out of 18 by Valencia as he scored points in every round.

Valencia MotoGP result:

1. Jorge Lorenzo ESP Movistar Yamaha MotoGP (YZR-M1) 45m 59.364s
2. Marc Marquez ESP Repsol Honda Team (RC213V) 45m 59.627s
3. Dani Pedrosa ESP Repsol Honda Team (RC213V) 46m 0.018s
4. Valentino Rossi ITA Movistar Yamaha MotoGP (YZR-M1) 46m 19.153s
5. Pol Espargaro ESP Monster Yamaha Tech 3 (YZR-M1) 46m 25.368s
6. Bradley Smith GBR Monster Yamaha Tech 3 (YZR-M1) 46m 28.199s
7. Andrea Dovizioso ITA Ducati Team (Desmosedici GP15) 46m 28.250s
8. Aleix Espargaro ESP Team Suzuki Ecstar (GSX-RR) 46m 33.586s
9. Cal Crutchlow GBR LCR Honda (RC213V) 46m 35.288s
10. Danilo Petrucci ITA Octo Pramac Racing (Desmosedici GP14.2) 46m 38.943s
11. Maverick Viñales ESP Team Suzuki Ecstar (GSX-RR)* 46m 39.110s
12. Michele Pirro ITA Ducati Team (Desmosedici GP15) 46m 46.417s
13. Yonny Hernandez COL Octo Pramac Racing (Desmosedici GP14.2) 46m 53.445s
14. Alvaro Bautista ESP Factory Aprilia Gresini (RS-GP) 46m 56.010s
15. Scott Redding GBR Estrella Galicia 0,0 Marc VDS (RC213V) 46m 56.642s
16. Hector Barbera ESP Avintia Racing (Desmosedici GP14 Open) 46m 56.727s
17. Nicky Hayden USA Aspar MotoGP Team (RC213V-RS) 46m 58.106s
18. Stefan Bradl GER Factory Aprilia Gresini (RS-GP) 46m 58.450s
19. Loris Baz FRA Forward Racing (Forward Yamaha)* 47m 3.703s
20. Toni Elias SPA Forward Racing (Forward Yamaha) 47m 3.777s
21. Jack Miller AUS LCR Honda (RC213V-RS)* 47m 4.576s
22. Anthony West AUS AB Motoracing (RC213V-RS) 47m 26.645s
Mike Di Meglio FRA Avintia Racing (Desmosedici GP14 Open) DNF
Eugene Laverty IRL Aspar MotoGP Team (RC213V-RS)* DNF
Broc Parkes AUS E-Motion IodaRacing (ART) DNF
Andrea Iannone ITA Ducati Team (Desmosedici GP15) DNF

Final riders’ World Championship standings:

1. Jorge Lorenzo SPA Movistar Yamaha MotoGP (YZR-M1) 330 points
2. Valentino Rossi ITA Movistar Yamaha MotoGP (YZR-M1) 325 points (-5)
3. Marc Marquez SPA Repsol Honda Team (RC213V) 242 points (-88)
4. Dani Pedrosa SPA Repsol Honda Team (RC213V) 206 points (-124)
5. Andrea Iannone ITA Ducati Team (Desmosedici GP15) 188 points (-142)
6. Bradley Smith GBR Monster Yamaha Tech 3 (YZR-M1) 181 points (-149)
7. Andrea Dovizioso ITA Ducati Team (Desmosedici GP15) 162 points (-168)
8. Cal Crutchlow GBR LCR Honda (RC213V) 125 points (-205)
9. Pol Espargaro SPA Monster Yamaha Tech 3 (YZR-M1) 114 points (-216)
10. Danilo Petrucci ITA Octo Pramac Racing (Desmosedici GP14.2) 113 points (-217)
11. Aleix Espargaro SPA Team Suzuki Ecstar (GSX-RR) 105 points (-225)
12. Maverick Viñales SPA Team Suzuki Ecstar (GSX-RR)* 97 points (-233)
13. Scott Redding GBR Estrella Galicia 0,0 Marc VDS (RC213V) 84 points (-246)
14. Yonny Hernandez COL Octo Pramac Racing (Desmosedici GP14.2) 56 points (-274)
15. Hector Barbera SPA Avintia Racing (Desmosedici GP14 Open) 33 points (-297)
16. Alvaro Bautista SPA Factory Aprilia Gresini (RS-GP) 31 points (-299)
17. Loris Baz FRA Forward Racing (Forward Yamaha)* 28 points (-302)
18. Stefan Bradl GER Factory Aprilia Gresini (RS-GP) 17 points (-313)
19. Jack Miller AUS LCR Honda (RC213V-RS)* 17 points (-313)
20. Nicky Hayden USA Aspar MotoGP Team (RC213V-RS) 16 points (-314)
21. Michele Pirro ITA Ducati Team (Desmosedici GP15) 12 points (-318)
22. Eugene Laverty IRL Aspar MotoGP Team (RC213V-RS)* 9 points (-321)
23. Katsuyuki Nakasuga JPN Yamaha Factory Racing (YZR-M1) 8 points (-322)
24. Mike Di Meglio FRA Avintia Racing (Desmosedici GP14 Open) 8 points (-322)
25. Hiroshi Aoyama JPN Repsol Honda Team (RC213V) 5 points (-325)
26. Takumi Takahashi JPN Team HRC (RC213V) 4 points (-326)