Stephen Costello vs Manuel Del Valle — ChatGPT betting tip 27 September 2025.

This matchup looks like a classic narrow-edge betting decision, and the market is telling us plenty. Stephen Costello is priced at 2.10 while Manuel Del Valle sits at 1.66. Converting those to implied probabilities, the book is asking you to believe Del Valle wins about 60.3% of the time and Costello about 47.6%—their sum (107.9%) reveals a healthy margin baked in. Strip out the vig and you get a no-vig split around 55.9% Del Valle vs 44.1% Costello, i.e., the market’s fair read is “slight favorite, not dominant.”

When prices say the fight is competitive, small underdogs often carry the value. MMA is inherently high-variance: tiny edges in timing, one scramble, or a single clean counter can swing the entire result, especially in three-round fights where judges reward damage and moments. Unless there’s a clear skill or athleticism gulf—and the current spread doesn’t suggest one—the dog is frequently the smarter side in the long run because you need less to go right to beat the number.

Mathematically, Costello’s break-even is just 47.6%. If this is closer to a coin flip than the board implies (say, Costello wins 50–52% in reality), the bet becomes +EV. With a $1 stake at 2.10, you profit $1.10 on a win. At 50%, your expected value is 0.50×1.10 − 0.50×1.00 = +$0.05 (a 5% edge). Even if you only rate him 49%, you’re still above the 47.6% threshold and squeaking out profit. By contrast, Del Valle at 1.66 needs north of 60.3% to break even—without strong, validated evidence of a consistent round-winning advantage (dominant wrestling loops, ironed-out cardio, reliable minute-winning tools), you’re paying a favorite tax that’s hard to justify.

Another angle: in competitive regional or mid-tier MMA, late camps, short-notice tweaks, and rapid skill development routinely compress gaps that markets overstate. That dynamic tends to benefit the underdog side because any incremental improvement or small tactical success disproportionately aids the plus-money ticket.

Bottom line: with a modest spread and a volatile sport, I prefer the side that wins if this fight is merely close. I’ll take the plus-money stance, trusting that the fight plays nearer to 50/50 than the chalk indicates. Give me Stephen Costello at 2.10 as the value bet for a $1 stake.