Doncaster RLFC’s Betfred League One title hopes suffered a setback following their 26-18 defeat against Keighley Cougars at Cougar Park.
The Dons led 18-12 at the interval after scoring four tries to two, but they only rarely threatened to add to their tally in the second half during which they lost two players.
The Dons got off to a flying start with on-loan centre Menzie Yere crossing for his second try in as many games.
Cheered on by an above-average Bank holiday crowd, Keighley hit back three minutes later to lead 6-4.
Jack Miller, one of four former Doncaster players in the Keighley ranks, broke the line prior to sending centre Macauley Hallett racing in from 40 metres out.
The Dons twice went close in as many minutes before Harris and winger Matty Chrimes featured in the move which saw Tali touch down out wide.
Cougars regained the lead when half-back Benn Hardcastle, who again added the extras, burrowed his way over from close range.
The lead changed hands for a fifth time after Tali touched down for a second try following work by winger Sam Doherty, who picked up a knock and was substituted a couple of minutes later.
His replacement, Elliot Townsend, extended Doncaster’s lead with a close-range try on 29 minutes.
There were chances at both ends - Chrimes saving a try on his own line prior to having one disallowed - in the closing stages of the half.
Cougars struck twice in the opening ten minutes of the second half to open up a 24-18 lead.
Apart from when Tali just failed to get on the end of a Bower kick over the line, the Dons rarely went close to a fifth try and a late Harcastle penalty sealed their fate.
Dons: Buchanan, Doherty, Tali, Yere, Chrimes, Howden, Harris; Douglas, Ogden, Boyle, Foster, Bower, Kesik. Subs: Spiers, Scott, Townsend, Hedges.