Dan Parks kicked two second-half penalties to help the Classic Lions topple South Africa, the defending champions, in an entertaining and often bad-tempered semi-final at the World Rugby Classic.

If there was any doubt about the Classic Lions’ intentions regarding winning their first title since 2008, then that was swiftly dispelled by their decision to break convention and kick penalties — the one thing that is usually frowned upon at the Classic.

Ultimately, the radar-like boot of Parks, the former Scotland fly half, proved to be the difference between the two sides in what was a closely-fought battle at North Field, National Sports Centre, last night.

Worryingly for the Lions, they could be missing both their star names at this year’s tournament, Mike Tindall and Iain Balshaw, when they face either New Zealand or Argentina, who play tonight, in Saturday’s final.

Both 2003 World Cup winners with England were forced off with injuries.

Allan Martin, the Lions coach, admitted that his side had claimed a huge scalp in beating the Springboks and were confident of ending their six-year barren spell.

“It was a tough old game, there was not a lot in it and it was nice to win,” said the former Wales player.

“You have to beat teams like this if you want to get to the final.”

Martin’s side made a slow start to the bruising encounter, falling behind after Jake Boer, the South Africa No 8, used his brute force to power over the line. The try was converted by Reinhard Gerber, the fly half. The Lions were struggling to get a grip on the game during this early period of South African dominance and matters got even worse when Tindall, the outside centre, hobbled off after ten minutes.

Ultimately, it was the hard running of Balshaw and the educated right boot of Parks that helped the Lions gain a foothold in the game, with the Springboks surviving some sustained late pressure to preserve their 7-0 lead at the interval.

Starting the second half as they finished the first, the Lions clawed their way back on level terms when Chris Fortey, the former Gloucester hooker, scrambled home for a try, which was converted by the reliable Parks.

Both teams were then reduced to 14 men when Chris Wyatt, the Lions lock, and Andries Human, the Springboks’ prop, received yellow cards after trading blows as the game turned into a scrappy affair, with neither side willing to surrender an inch to each other. Moments later, the game seemed in danger of descending into a sevens match — which would have been quite apt considering Dave Keane, the referee, has officiated the most sevens games in world rugby — when Dave Corkery, the former Ireland flanker, and Norman Jordaan, the South Africa scrum half, were sin-binned after a one-on-one punch up.

Lions nudged ahead on 45 minutes through a Parks penalty before having another player yellow carded, Rory Jenkins, the flanker, for a late tackle. Parks kicked his second penalty in the 55th minute to put some daylight between the two sides, with Lions enduring a nervous finale as South Africa poured forward in a last-ditch attempt to keep their title defence alive.

“It was very competitive, you wouldn’t expect it to be any other way,” Martin added. “It means a lot to both teams to win the Classic — it just got a little overheated.”