The May-December collaboration between tenor saxist Eric Alexander and veteran pianist Harold Mabern, 32 years his senior, began more than a dozen years ago, and it remains one of the most fruitful relationships in mainstream jazz. (It probably helps that both spent their early 20s in Chicago, absorbing the city’s hard-charging, blues-inflected approach to improvisation.) With Mabern’s blocky chords and juggernaut swing as their foundation, Alexander’s solos explode out of the gate and never flag, piling up inventive melodies as they hurtle to the finish; he’s polished his playing over the years, and in the process he’s become one of the most consistently satisfying soloists on the instrument. On his latest album, this year’s It’s All in the Game (HighNote), Alexander stays true to the formula that’s worked well on most of his discs, assembling standards like “Where or When,” a few of his own compositions, and surprises like the Roberta Flack & Donny Hathaway hit “Where Is the Love” and the title track, a breezy staple of 50s and 60s pop into which he pours all of his huge, splendiferous tone. See also Wednesday and Thursday; the quartet’s run continues through November 12. a 8 and 10 PM, Jazz Showcase, 59 W. Grand, 312-670-2473, $20.