(CNN) -- When Yamaha announced that Valentino Rossi would return to the champion motorcycling team this season, many wondered if he would be able to repair his previously fractious relationship with teammate Jorge Lorenzo.
However, the threat to Lorenzo's status as world champion is coming from an unexpected source -- Honda's rookie MotoGP rider Marc Marquez.
The 20-year-old has won his last two battles with Lorenzo, becoming the youngest winner of a top-level race in Austin, Texas last month and then on Sunday edging his fellow Spaniard into third place after an audacious final-corner overtake which saw the two bikes make contact.
What made it harder for Lorenzo to bear was that it came at the part of the Jerez track which had been named in his honor ahead of this weekend's Spanish Grand Prix.
"If somebody did that to me ... for sure, I would be angry," Marquez told the MotoGP website.
"Not because of the moment but because I would have lost a place on the podium. I can understand that but, anyway, I have said sorry.
"I thought he would close the corner off a little bit more than he did, but I noticed that he had opened the door so I tried to pass him. When I saw in those last meters that I might touch him, I released the brakes a bit to make sure the touch was going to be a bit softer.
"The most important thing is that we both finished and I just hope that our relationship will get a bit better after a few days."
The result left Marquez on his own at the top of the championship standings, while Lorenzo dropped to third behind race winner Dani Pedrosa.
"I was second all race and lost it at the last corner," Lorenzo said. "Anyway, our bike was not very competitive compared to the Hondas.
"I had a very consistent race, just making two mistakes: I started very badly and didn't close the door enough at the last corner."
Pedrosa celebrated his first win this season and his first at his home race since 2008.
"It was a beautiful race," the Honda rider said. "I was able to ride the bike well, even though it was difficult because the tires were really on the limit. I couldn't push too hard because of that, so I had to ride carefully."
Seven-time world champion Rossi finished fourth ahead of Britain's Cal Crutchlow on a Monster Yamaha Tech 3.
"Unfortunately, I didn't have enough pace at the beginning because we did not find the right balance," said Rossi, who is also fourth overall -- 18 points behind Marquez ahead of the next race at Le Mans.
"We have to work very hard -- especially because Lorenzo is faster than us -- so we have to find the right balance and work together with Yamaha because in this race we expected to be stronger than the Hondas but in the end we have finished behind them, so we have a lot of work to do."