Career
Sekiguchi began his career competing in the 1999 250cc Japanese Grand Prix. In 2006, he raced in the 250 Grand Prix class with the number 44, for team Campetella Aprilia, alongside Chaz Davies. He suffered a serious accident in the 2007 Czechoslovakian Republic Grand Prix at Brno, where he struck Marco Simoncelli"s Gilera bike at full speed.
He was airlifted to a hospital in Brno, where doctors confirmed he had a broken pelvis and two fractured ribs.
After losing his Grand Prix ride, Sekiguchi returned to Japan, returning to the MFJ All Japan Road Race GP250 Championship. He moved into the MFJ All Japan Road Race ST600 Championship in 2009, before moving into the MFJ All Japan Road Race J-GP2 Championship, finishing as runner-up in 2011, 8th in 2012, 12th in 2013 and 6th in 2014.
He continues in the J-GP2 series for 2015. (key) (Races in bold indicate pole position.
Races in italics indicate fastest lap).