Handscomb, who's had a fine season leading Leicestershire to the top of division two of the County Championship, had a landmark Sunday, scoring his third hundred of the season while going past 20,000 career runs in all forms of the game.
Alas, the 34-year-old couldn't end his big day with what he really wanted as Leicester were edged out by three wickets at Bristol by a Gloucestershire side featuring his old international colleague Cameron Bancroft.
But 33-year-old Harris, who was entrusted mid-season with taking the reins at struggling Lancashire, had much to smile about as he cracked a match-winning 95 in their two-wicket victory over Somerset at Taunton.
Handscomb has had a terrific summer at Grace Road, having notched a couple of championship centuries and been widely praised for his shrewd captaincy.
His 107 off 125 balls, featuring nine fours and a six over long-off to reach three figures, was the Victorian's ninth list-A hundred and looked well set to earn Leicester a win in England's premier 50-over competition as they amassed 7-285.
But Gloucestershire, given a bright start by Bancroft (40 off 49) and the brilliant James Bracey (96 off 106 balls), eked their way to victory when rookie batter Tommy Boorman saw them home with 33 not out with nine balls remaining.
At Taunton, Harris, who is also closing in on 1000 county championship runs this season, again proved inspirational as he led the chase of Somerset's 7-250 with his eighth score of 50 or more this season with Lancashire.
He looked odds-on to record his fourth ton of the summer after cracking seven fours and two sixes, but, off the 99th ball he faced, finally succumbed to the left-arm spin of Lewis Goldsworthy, giving a catch to Kian Roberts at mid-off with five needed.
But along with George Balderson, with whom he'd shared a century partnership for the fifth wicket, Harris had set Lancashire on the way to a victory with eight balls to spare.
Another Australian in the runs on Sunday was Tasmanian Caleb Jewell, who continued his magnificent summer for Derbyshire with a brisk 60 off 70 balls at the top of their innings against Nottinghamshire at Derby, setting the tone for his side's eventual 127-run win.
