Marc Marquez has taken his first ever grand prix victory by just 0.039sec, as the top four riders in Sunday's 125cc Italian Grand Prix at Mugello crossed the line within 0.161sec.
Title leaders Nico Terol and Pol Espargaro made an early break, but were caught after eight laps by Marquez and Bradley Smith - with the top four riders then seesawing back and forth until the end of the race.
The 20th and last lap began with the Ajo Derbi of Marquez leading the Tuenti Derbi of Espargaro, followed by the Aspar Aprilias of Terol and Smith.
Terol then got the better of Espargaro, but Marquez clung doggedly to the lead and was just able to avoid being mugged during the long run to the line. 2010 is Marquez's third year in grand prix racing.
Terol remained closest to his fellow Spaniard - as consecutive Spanish wins in the 125cc class reached 14 - and has increased his title lead slightly to six points over Espargaro, who had won the last two races.
Marquez is third, but 28 points from the top after crashing out at Jerez.
2009 Mugello winner Smith, without a podium in the first three rounds of this season, led significant parts of the race but was left fourth at the flag.
Smith has suffered from a lack of outright performance from the machinery in the opening rounds and he later indicated that had once again been a factor in the race.
Pole sitter Sandro Cortese crashed from the lead group on lap two, and then fell again later in the race, ending his day.
Race results - Mugello:
1. Marquez (Derbi) 20 laps
2. Terol (Aprilia) +0.039s
3. Espargaro (Derbi) +0.116s
4. Smith (Aprilia) +0.161s
5. Vazquez (Derbi) +10.281s
6. Krummenacher (Aprilia) +10.364s
7. Rabat (Aprilia) +10.562s
8. Koyama (Aprilia) +36.341s
9. Zarco (Aprilia) +36.411s
10. Webb (Aprilia) +36.730s