Having dispatched early-season title rivals Loughborough Students convincingly the previous time out in National One, few outsiders will have thought a trip to Oxfordshire would provide many problems.
But an unbeaten home record for the Hawks at Dry Leas stretching back to November 12 indicated they were unlikely to be a pushover, and so it proved.
A measure of how tough the hosts were going to prove to crack was evident when they enjoyed the better of the early exchanges.
In the sixth minute, after the Knights infringed at a driving line out, on-loan full-back Will Robinson lined up what was a tricky kick at goal, but slotted it over comfortably.
Doncaster were hindered two minutes later when Michael Hills was forced off to be replaced by Adam Kettle.
It was the hosts who rattled the scoreboard once again halfway through the first half, Robinson again proving clinical to double his side’s lead.
Further injury troubles then transpired for director of rugby Clive Griffiths’s side when No 8 Christopher Eggleshaw went off with what looked like a shoulder injury, Ben Hunter coming on to replace him.
In the period leading up to half-time, Doncaster enjoyed their best period of the match and pulled themselves back to within a point of Henley when Glenn Bryce and Bevon Armitage combined for Hunter to score, although the kick from Roberts sailed wide.
Kettle was then sent over the line for Doncaster – again Roberts could not plant the kick – to see the visitors go in 10-6 ahead.
That is how it remained until the 51st minute when Robert Stapley was driven over by the Henley pack for what proved to be a match-winning try.
Griffiths’s team remain top of the league table despite the setback, with second-placed Rosslyn Park closing the gap to three points following their 48-17 win over third-bottom Worthing Raiders.
Doncaster will attempt to bounce back on Saturday when they welcome second-bottom Tynedale to Castle Park
Henley Hawks: O’Neill, Robinson, Nutt, Allen, Incldeon, Robinson, Carter; Milford, Brennan, Penny, Clements, McNally, Woodward, Long, Stapley. Replacements: Maddocks, Hadfield, Hayes, Bruce, Cobden.
Tries: Stapley 51. Pens: Robinson 7, 20.
Doncaster Knights: Bryce, Jarvis, Clark, Armitage, Slater, Roberts, Bravo; Cosgrove, Santamaria, Phillips, Challinor, Walker-Fitton, Jones, Hills, Eggleshaw. Replacements: Morris, Hunter, Kettle, Field, Davies.
Tries: Hunter 35, Kettle 39.
Referee: Phillip Davies (RFU).