Dani Pedrosa looked to be on target for a repeat of his dominating 2002 victory at Motegi today, but mid race mechanical problems left him vulnerable to the battling trio of Hector Barbera, Casey Stoner and Andrea Dovizioso.
Qualifying saw Pedrosa take his ninth pole in the 125cc class by a clear margin, setting a best time of 1min 57.736secs to beat his own previous record at the circuit and secure the front spot by a clear 0.822 seconds.
His closest rival was Stefano Perugini, with the Italian desperate for victory as he trails the Spaniard by some 42 points in the championship. However, Perugini's best lap came at the very end of a relatively sterile session devoid of serious challengers to Pedrosa's seniority.
Jorge Lorenzo, winner of the last race at Rio, sealed his third front row start of the season in third place whilst Hector Barbera made it three Spaniards in the top four.
Provisional pole setter Dovizioso was unable to improve his time and slipped to the second row in fifth place, ahead of Pablo Nieto, Lucio Cecchinello and Alex De Angelis.
When the red lights went out, Pedrosa converted his pole into the holeshot and led the 38-rider field through the first turn, ahead of Barbera, Talmacsi, Perugini, Kallio and Dovizioso. However, 16-year-old Barbera wasn't going to let his countryman run away (as he did one year ago) and dived inside the Telefonica rider early in the lap.
Dani, riding his spare bike after warm-up problems, fought back towards the end of the lap – and would lead the field over the finish line for the first time ahead of Barbera, Dovizioso, Talmacsi, Kallio, Perugini, de Angelis, Jenkner and Masao Azuma, who last night announced he'll be retiring at the end of the year.
Having survived the early assault from Barbera unscathed, Pedrosa soon began setting an unmatchable pace to pull away from the field, while behind him Dovizioso, Barbera and Stoner were locked in battle for second, with Perugini, Kallio and Jenkner remaining in touch.
By lap 10 of 21, Pedrosa's advance had been pinned by Dovizioso, Stoner and Barbera to just over a second, while Rio winner Lorenzo and podium regular de Angelis had joined what was now a nine-way battle for victory.