Bath hooker Lee Mears claimed the tourists' first try of the night after 23 minutes before the Magners League quartet put the game beyond their South African opponents during a convincing second-half display.
A total of 13 Magners League players started the game at the venue of the first Test against the Springboks, with Mears and Tom Croft the only players from outside the league in the chosen XV.
Three more Magners League players made an appearance from the bench, with Matthew Rees, James Hook and Mike Blair all getting game time in the Lions' fourth successive victory on their 10-match tour.
Munster fly-half Ronan O'Gara kicked 12 points while Ospreys No10 James Hook added the final conversion as the Lions eased home 39-3 following a tough first half.
The Lions began brightly and spent the vast majority of the opening quarter penned in Sharks territory but they had to wait until the 23rd minute before putting points on the board.
Cardiff Blues centre Jamie Roberts made hard yards on one particular charge, while Heaslip was driven over the line only to be held up by the home defence with 11 minutes played.
Leinster's Brian O'Driscoll was caught five metres from the Sharks line following a 75-metre interception and O'Gara turned down two kickable penalty attempts in exchange for a kick to the corner on each occasion, with the Lions unable to turn pressure into points until Mears' timely intervention.
The Bath and England hooker used his 5ft 8in frame to his advantage to burrow over from close-range following impressive work from Phillips and Heaslip.
Phillips cut back inside having dummied to move the ball away at a ruck 10 metres from the try line and, although his break was far shorter than some of his more talked about efforts for the Ospreys and Wales, it was enough to draw in two defenders and put the Lions on the front foot.
Heaslip was on hand to keep the Lions moving forward as he carried Phillips' offload into two more Sharks, with Mears then reacting quickest at the ensuing ruck.
O'Gara built on his tally of 22 points from the opening day win in Phokeng with a well-taken conversion from two metres inside the 15-metre line on the left-hand side as the Lions finally gained some reward for their first-half dominance.
Paul O'Connell's side continued to enjoy the upper hand for the remainder of the half but the Sharks defence held firm for the closing 17 minutes and it was they who were the next to score.
Scrum-half Rory Kockett, who started for a Namibian Invitational XV against the Springboks a fortnight ago and has kicked ahead of Bok fly-half Ruan Pienaar during this year's Super 14, slotted a relatively straight forward penalty attempt to bring the Sharks back to within four points with half an hour gone.
The Lions came close to a second try on the stroke of half-time after Shane Williams and Byrne contested O'Gara's cross-field kick but a marginal knock on from Williams prevented his Ospreys colleague from following up on his fine try in the 37-25 win over the Royal XV 11 days ago.
McGeechan's class of 2009 only had to wait the duration of the half-time interval and a little extra before adding to their tally, however, with Phillips continuing his strong start to the tour by finding a way through the Sharks defence from the edge of the opposition 22 just two minutes into the second period.
O'Gara sent his conversion attempt narrowly wide to register his only blemish on an otherwise impeccable display when kicking for goal but the Lions had finally moved more than one score clear at 12-3.
Kockett missed an opportunity to bring the Sharks back to within touching distance two minutes later as he fell short with a 45-metre penalty and O'Gara made the home side pay with a brace of penalties of his own on 48 and 52 minutes.
The try of the match arrived seven minutes later as the Lions showed the Springboks exactly what they are capable of when given quick ball to play with.
Heaslip's quickly-taken tap following a free-kick offence at a scrum on the Lions' 10-metre line saw the Lions reach halfway, with possession recycled quickly allowing Tom Croft to feed Brian O'Driscoll in space.
The 2005 Lions skipper raced 35 metres with a fine outside break before his change of angle 10 metres out left Sharks full back Stefan Terblanche in no man's land and gave Fitzgerald an easy finish.
O'Gara added a fine conversion from narrowly inside the left touchline and the Lions found themselves with a 22-point advantage with an hour on the clock.
Byrne then crossed for a fourth Lions score and his second of the tour after bursting through the smallest of gaps on halfway, handing off one defender and then powering through the tackle of two more on his way to a fine individual try.
O'Gara's extras made it 32-3 in the Lions' favour with 12 minutes remaining before Heaslip added the coup-de-gras with the final play of the match.
The Ireland No8 gained his reward for an industrious display in both the tight and the loose as he squeezed through the Sharks defence following another quickly-taken tap five metres short of the try line.
The Leinsterman was brought down just short initially but he stretched over in the same movement to put the gloss on a hard-earned with for the Lions.
Replacement fly-half Hook kicked the straightforward conversion from just to the rights of the uprights and the Lions left the ABSA Stadium with a handsome victory over a fully-committed opposition.
With the first Test against the world champions now just 10 days away, the Lions turn their attentions to the next stage of their preparations - Saturday's clash with Western Province in Cape Town.
The fifth opposition of the tour have traditionally given the Lions a tough time, with a Western Province triumph in 1938 followed by five Lions victories by nine points or less prior to the Lions' 38-21 win at Newlands 12 years ago.
McGeechan and his fellow coaches will be hoping the current crop of Lions can make it five wins from five as the possible make up of the Test team starts to become more apparent.
63x46.png){kind=logo}