He delivered an all-action display as Clive Griffiths’s side recovered from 21-8 down early in the second period against a prolific side who had won all five previous British & Irish Cup pool games.
Tyrell led from the front with some huge defensive hits as Doncaster secured a quarter-final place, their opponents yet to be decided.
At 21-8 ahead, Leinster were reduced to 13 men when both lock Ian Hagle and full-back Barry Daly were yellow-carded around the 50th minute, the latter’s deliberate knock-on also ending in a penalty try.
Doncaster full-back Paul Jarvis then scored a dazzling 80m solo effort before – with Leinster back up to 15 – winger Junior Bulumakau got the score that put Knights ahead.
Industrious captain Matt Challinor added their fifth try in a dominant second-half performance, putting to bed painful memories of the previous week’s home defeat to Bristol when Knights gifted their rivals two intercept tries.
Two-time Cup winners Leinster – so impressive in this competition – rumbled over via Sean McNulty’s in added-time, but it was too little too late.
Earlier, Knights prop Joe Sproston opened the scoring before Leinster showed their class, three slick tries via Gavin Mullin, Ed Byrne and Nick McCarthy giving them a 21-8 lead in 25 minutes.
However, it would not be enough versus Doncaster who return to Championship action at Nottingham on Sunday.