It was always going to be a frenetic final Friday night with Connacht away at Edinburgh and Ulster at home to Glasgow.
With Glasgow, Stormers, Leinster and Bulls having booked their play-off places, Lions, Munster, Cardiff and Ulster started the final round in the remaining spots with ninth-placed Connacht just outside.
Cardiff were in in seventh place, aiming to book the play-off place, while Stormers were second and hoping to seal top spot so they would be at home in a potential quarter-final, semi-final and final.
Cardiff were desperate to avoid history repeating itself, after they missed out on finishing in the top eight last season by just one point to fellow Welsh side Scarlets.
They managed this in style.
Lock Josh McNally was unavailable because of selection to play for the Royal Air Force against the British Army tomorrow, while Wales forwards Alex Mann, Teddy Williams and Taulupe Faletau were also missing.
Halfpenny was named on the replacements bench after stepping in due to a number of backline injuries, including Wales trio Callum Sheedy, Josh Adams and Mason Grady.
Fly-half Lloyd replaced Sheedy but made an early error from the kick-off which put the home side under pressure.
Cardiff captain Liam Belcher was shown a yellow card for conceding a penalty on his own line while the hosts' scrum was under intense pressure.
It was no surprise when Smith powered over and Feinberg-Mngomezulu converted.
Cardiff responded well as they firstly ran down the clock when they were down to 14 men with some effective close-quarter attacks, heavily involving Basham.
The home side capitalised when they were back to a full complement with a clever Lloyd cross-kick finished by Beetham with the fly-half converting from the touchline.
Cardiff were rampant and, with centre Ben Thomas at the helm, the hosts created an excellent second try for Wales Under-20s wing Bowen, who superbly squeezed in down the left corner.
After the initial dominance, Stormers were unsettled but managed to reduce the deficit with a long-range Feinberg-Mngomezulu penalty.
Cardiff prop Danny Southworth looked as if he had scored the hosts' third try but it was disallowed because of a forward pass.
Smith was shown a yellow card for a high and dangerous tackle on Botham just before half-time as Cardiff made the extra player tell.
It was Lloyd that wriggled into the corner with another fine finish to give Cardiff a 17-10 interval lead.
Cardiff: Winnett; Beetham, B Thomas, Jennings, Bowen; I Lloyd, Mulder; Southworth, Belcher (capt), Sebastian, Nott, Thornton, Botham, D Thomas, Basham.
Replacements: D Hughes, Barratt, Assiratti, Lawrence, E Lloyd, E Bevan, S Emanuel, Halfpenny.
Yellow card: Belcher 5
Stormers: Willemse; Hartzenberg, Simelane, Roche, Zas; Feinberg-Mngomezulu, Khan; Mchunu, Venter, Fouche (capt), Smith, R van Heerden, P de Villiers, B-J Dixon, Roos.
Replacements: Kotze, Kebble, Sande, Moerat, Theunissen, Morabe, Ungerer, Matthee.
Yellow card: Smith 38, Hughes 80
Referee: Andrew Brace (Ireland)
Assistant referees: Ben Connor (Wales), Lucas Yendle (Wales).
TMO: Olly Hodges (Ireland).
Extracted and lightly reformatted for readability. · Source: pt
