The Belarusian won the penultimate stage of the Giro after a superb solo ride over the two climbs of the day, the precipitous Colle delle Finestre and the steady ascent to Sestriere in the Italian Alps.
Kiryienka's team-mate Tondo was killed last Monday in a freak domestic accident when he was trapped between his garage door and his car before heading out for a training ride.
The victory marked the first opportunity a Movistar rider has had to dedicate a victory to Tondo - although Spain's Alberto Contador, the race leader, did pay his respects to his fellow countryman after winning Tuesday's individual mountain time trial.
Kiryienka was part of a 13-man breakaway which formed on the initial flat part of the 242km stage from Verbania to the popular ski resort near the French border.
The group, which also included stage 18 winner Diego Ulissi and the race's most combative rider in RadioShack's Jaroslav Popovych, built up a large lead of 12:30 before the feeding zone.
But hard work on the front of the peloton by Liquigas, AG2R and Saxo Bank saw the gap whittled down to just six minutes at the foot of the first category Colle delle Finistre climb, 45km from the finish.
With the lead dropping fast, Kiryienka took matters into his own hands, breaking clear on his own and riding solo over the narrow gravel track to the summit.
Venezuela's Jose Rujano (Colnago) - who won a similar stage to Sestriere in 2005 in devastating fashion - attacked from the main pink jersey chasing group, catching all the remaining escapees by the time he reached the summit, 3:45 down on the lone leader.
The 29-year-old Kiryienka increased his lead on the quick descent and started the final ascent to Sestriere with a large 4:20 minute advantage over Rujano and Carlos Betancourt (Acqua & Sapone).
Despite the win all but assured, Kiryienka kept his focus with an assured display of climbing - and it was not until the finishing straight that the all-rounder showed a bit of emotion.
After shaking the hand of his directeur sportif, Kiryienka took a drink, put on his sun glasses and then broke out in a big grin. Crossing the line after six hours and 17 minutes in the saddle, Kiryienka then pointed to his sponsor's logo and a black ribbon in memory of Tondo, before raised both hands towards heaven.
It was Kiryienka's second career win in the Giro following success in stage 19 of the 2008 edition.
Rujano took second place, 4:43 behind, before Joaquim Rodriguez (Katusha) came home a further six seconds down.
Contador finished in a select chasing group of riders, just under six minutes off the pace, to retain his maglia rosa ahead of Sunday's final stage, a 26km individual time trial in Milan.
The Saxo Bank rider leads Michele Scarponi (Lampre) by 5:18 and Vincenzo Nibali (Liquigas) - who lost 26 seconds to his rivals on the final ascent - by 6:14.
Despite failing to pick up any further points on Saturday, Italian Stefano Garzelli (Acqua & Sapone) secured the overall green jersey as best climber.
- Related links