The Blues had not won at home since they thrashed Scarborough 5-0 on October 15 but they got that monkey of their backs with a dogged victory that owed more to character and determination than to free-flowing football.
Oli's 69th minute winner, his first since a brace against Crawley on September 24, was in keeping with a scrappy game that seemed destined to be settled by a single goal.
Grays' best player on the day, Michael Kightly, looked to have won a free-kick on the edge of the area but, as the referee waved play on, the ball was fed into the box and Leo Mendy's attempted clearance ricocheted off his own team-mate and into the path of Oli, who coolly slotted past Phil Smith.
Grays had a great chance to open the scoring in just the 11th minute when Aaron McLean's knock-down found Jamie Slabber alone in the box.
But the ex-Aldershot man is so low in confidence right now he never looked like rounding the move off and Ben Judge was allowed to hack the ball clear from his own goal-line.
Crawley's best chance of the opening half fell to Daryl Clare who was put in by Tony Scully, but shot tamely at Ashley Bayes from a good position.
Oli came close to breaking the deadlock ten minutes before he actually did so when he headed Stuart Thurgood's free-kick just past the post, but that didn't matter in the end when he popped up to score the winner 21 minutes from time.
Oli's 69th minute winner, his first since a brace against Crawley on September 24, was in keeping with a scrappy game that seemed destined to be settled by a single goal.
Grays' best player on the day, Michael Kightly, looked to have won a free-kick on the edge of the area but, as the referee waved play on, the ball was fed into the box and Leo Mendy's attempted clearance ricocheted off his own team-mate and into the path of Oli, who coolly slotted past Phil Smith.
Grays had a great chance to open the scoring in just the 11th minute when Aaron McLean's knock-down found Jamie Slabber alone in the box.
But the ex-Aldershot man is so low in confidence right now he never looked like rounding the move off and Ben Judge was allowed to hack the ball clear from his own goal-line.
Crawley's best chance of the opening half fell to Daryl Clare who was put in by Tony Scully, but shot tamely at Ashley Bayes from a good position.
Oli came close to breaking the deadlock ten minutes before he actually did so when he headed Stuart Thurgood's free-kick just past the post, but that didn't matter in the end when he popped up to score the winner 21 minutes from time.