Both sides scored six tries apiece and each team succeeded with five conversions, which saw them heading into the final straight with the scores locked at 40-40 after 80 minutes of incredible attacking rugby.
However, Cell C Sharks captain Lukhanyo Am ventured offside at a breakdown and that transgression was enough to present Swanepoel with an easy penalty goal attempt.
The home team, captained by Springbok flyhalf Elton Jantjies, led 26-14 at the break in this 2021 Kick-off Pools clash.
Ngia Selengbe, Swanepoel, Vincent Tshituka, Courtnall Skosan, Dan Jooste and Wandisile Simelane scored a try each for the Joburg side, while Swanepoel (2) and Jantjies (3) succeeded with five conversions between them.
Forward replacements Dylan Richardson (hooker) and Ntuthuko Mchunu (prop) each managed to score two second half tries apiece for the visitors, to add to the first-half tries by Aphelele Fassi (fullback) and Werner Kok (right wing).
Swanepoel’s three-pointer in the 83rd minute was the only penalty goal in the match, as both teams elected to rather have a go at try-scoring opportunities, which netted a combined total of 12 tries.
The Lions finished the first half firmly in control having outscored the visiting side by four tries to two. They displayed their attacking intent with a couple of eye-catching long-range tries, while also showed their teeth when mattered on defence, such as their effort right at the end of the first stanza to deny the Cell C Sharks from scoring a third try.
The first half was an entertaining affair, which netted no less than six tries. The slick handling made up for the struggles by both sides in the set-pieces, which can no doubt be attributed to the experimental make-up of both teams.
With the Cell C Sharks determined to claw their way back, the Lions repelled several attempts by the visitors' pack at the start of the second half.
With Lions prop Carlu Sadie sent to the sin bin, it was no surprise that the Cell C Sharks elected to maul towards the Lions’ line for a third successive time, with Richardson crossing the whitewash.
This has to be one of the best-ever prop tries you are likely to see by Ntuthuko Mchunu in the Sharks' 40-43 loss to the Lions. The commentary around 30 seconds though 🤣🤣 pic.twitter.com/85EJYOWDFJ— SuperSport 🏆 (@SuperSportTV) March 20, 2021
Boeta Chamberlain (flyhalf) hit the mark with his second conversion to reduce the deficit to 26-21 with plenty of time left on the clock.
However, in keeping in sync with their lineout woes, the Cell C Sharks bungled a throw in on their goal line, allowing Lions hooker Jan-Henning Campher to score an easy try, which Swanepoel converted to stretch their advantage to 33-21.
Richardson then atoned for his previous mistake when he forced his way over for his second try of the afternoon which was converted by Springbok Curwin Bosch, who had come onto the field a few minutes earlier as the replacement flyhalf (33-28).
Mchunu made a great impact for the visitors when he scored two quick-fire tries which allowed the coastal side to level matters at 40-40 after Simelane had scored an acrobatic try for the Lions, "intercepting" a cross-field kick deel in the Cell C Sharks' territory.
With the clock winding down, Simelane had a wonderful opportunity to score his second try and the winning points for the Lions, but he was felled just short of the whitewash by a bout of cramps.
With the game heading for a high-scoring stalemate, Swanepoel easily steered his injury-time penalty goal kick through the sticks for a dramatic home win.
Lions 43 (26) - Tries: Ngia Selengbe, Tiaan Swanepoel, Vincent Tshituka, Courtnall Skosan, Jan-Henning Campher, Wandisile Simelane. Conversions: Swanepoel (2), Elton Jantjies (3). Penalty goal: Swanepoel.
Cell C Sharks 40 (14) - Tries: Aphelele Fassi, Werner Kok, Dylan Richardson (2), Ntuthuko Mchunu (2). Conversions: Boeta Chamberlain (3), Curwin Bosch (2).