Colts stands a chance of securing back-to-back Bunbury and Districts Cricket Association premiership titles.
In round 18, Colts' opening batsmen Jaysen Miguel (7) was caught by Dalyellup Beach's Corey Fagan.
Colts then slipped to 2/8, after bowler Zane Verhaaf (2/47 from two overs) dismissed top order batsman Murray Goodwin for one.
Fellow opener Jayden Goodwin slogged 32 to get his side back on track, before Blaze Rosinski made a delightful 65.
After a middle order slump and solid batting from the tail-enders, Colts made 9/187 from 50 overs.
Dalyellup's inning began with solid efforts from Mitchell Boyle (14), Justin Woods (52, including four fours), and captain/wicketkeeper Paul Jones (36).
Middle and lower order collapses diminished Dalyellup's chances at victory. After 50 overs, the side posted 9/149.
Fifth-placed Marist claimed an upset victory over league leaders Eaton.
Top order batsmen Don Seaman (84, including nine fours and two sixes) and Christopher Marrow (49) starred for the Beavers.
Going after Eaton's 9/240, Marist's Ben Clarke (86), Kyle Davis (43), and captain Reece O'Connell (41) all impressed with the bat.
The Blues were elated after reaching Eaton's total with nine balls remaining.
Hay Park scored a 33-run win over third-placed Leschenault in a low-scoring affair.
Jono Whitney was Hay Park's saviour, knocking 24 off 74 balls.
The Redbacks lasted 44.2 overs before being dismissed for 104.
Leschenault's inning went from bad to worse, with Michael Newman (16) the only batsman to reach double figures.
The Green Caps were all out for a miserable 71.
Colts cruised to a 92-run victory over Marist at Forrest Park North in round 19.
Half-centuries from Cruize Ciallella and Riley Miguel helped the reigning premiers to a 5/218 total.
Blues' batsman Jordan Stynes notched up 47, before Marist was dismissed for 126 with 10 overs to spare.
Eaton suffered its second consecutive loss after falling short by 60 runs against Hay Park.
Spells from Stuart Hayward (28 off 44), Kris Miller (26 off 47, including five fours), and Callum Wood (24 off 35) assisted the Redbacks in reaching 147.
Hay Park needed just 28.1 overs to dismiss the Beavers for 87.
Leschenault remains third following its win over Dalyellup Beach on Saturday afternoon.
Despite a middle order slump, the Green Caps still managed 9/184.
The Beach Boys' inning fell apart late in the day, with the side all out for 111 with nine overs to go.