Holders Harryville Homers took another step closer towards retaining the O'Kane Cup, with a thumping four-goal defeat of Randalstown Athletic on Saturday.
Despite enjoying the lion's share of possession in the first half, they failed to find a way past their Second Division opponents.
And when Stevenson hit the bar early in the second half, they might have been forgiven for thinking that it was going to be one of those days.
However, the long awaited breakthrough eventually arrived just after the hour mark, when Bonnes knocked an Alan Rainey ball on, enabling Stevenson to cross for John McDowell to head home.
Stevenson made it 2-0 soon after, when he pounced on a poor clearance to round Athletic 'keeper David Irvine. Barry McDowell then added a third on 80 minutes, with a low 20-yard drive.
Bonnes completed the scoring right at the end, when he collected a Timmy Hume ball to beat the offside trap.
The team will be joined in the last four by great rivals Carniny Rangers, who came through a somewhat tighter 3-1 victory of FC Moylena.
Roger Jones handed them the advantage after a quarter of an hour, when he out-sprinted the defence to slot the ball into the bottom corner.
Moylena almost levelled when a Paul Milliken snap-shot came back off the post.
But they didn't have to wait too much longer to equalise, when Victor Gordon poked the ball through a crowded penalty area on the half-hour.
However, Carniny still went in at the break back in front, when Robinson collected the ball from Marcus Sprint, to finish well just as the whistle was about to blow.
Moylena battled hard in their quest for a second equaliser after the break, but despite ensuring Alex McCosh was kept busy, their efforts proved in vain.
Indeed, Carniny made sure of their semi-final berth right at the end, when Robinson knocked home a penalty awarded for a foul on player-manager Robert Young.
In Division One, leaders Holywell lost again (5-4 to All Saints OB), with Glenarm Rovers joining them on 19 points, after a 5-2 defeat of Waveney Swifts.
The Division Two title tussle took another twist, when Ballykeel defeated leaders North End by a single goal, to join them on 22 points.
In Division Three, FC Inter Stars stretched their lead to six points, after a draw with Shore Wanderers.