South Africa head coach Jacques Nienaber has defended his decision to make 14 changes to his starting line-up for Sunday's Rugby World Cup Pool B match with Romania in Bordeaux.

"We're fully focused on Romania because we should show them that respect. It's only the second time we've played them in a World Cup, so it's a special game for us," said Nienaber.

"There is a definite objective that we want in this game, and points difference might come into play in this pool, but the first thing is we need to back up the opening win.

"There is definitely some tactical and technical stuff that we want to get out of this game, and that is our challenge - to get what we want out of this game."

The world champions are without hooker Malcom Marx, who has been ruled out of the tournament with a knee injury, and lock Eben Etzebeth because of a shoulder problem.

Etzebeth should be fit in time to return to face the world's number one side Ireland on 23 September, while Marx's replacement in the 33-man squad has yet to be announced.

Bongi Mbonambi starts at hooker, with Deon Fourie on the bench.

Nienaber has named four scrum-halves in his matchday 23, with Cobus Reinach starting, Jaden Hendrikse on the bench, Grant Williams on the wing and Faf de Klerk the back-up fly-half.

Number 10 Manie Libbok has been rested, so Willemse starts.

"I'm not being disrespectful to Romania but it's an opportunity to try him out in a Test match under pressure at 10," Nienaber said of Willemse.

"He's trained there for us numerous times. We've said Faf is our third-choice fly-half but this is a nice opportunity to give him a run at 10, controlling the game at 10 at Test-match level."

Romania head coach Eugen Apjok has made three changes, including a World Cup debut to flanker Andre Gorin at the age of 35, following their 82-8 defeat by Ireland in their opening fixture.

Apjok said: "After the world number one team Ireland, then South Africa, second in the world and the world champions, you can only be enthusiastic."

Line-ups

South Africa XV: Le Roux, Williams, Moodie, Esterhuizen, Mapimpi, Willemse, Reinach; Nche, Mbonambi, Koch, Kleyn, Orie, Van Staden, Smith, Vermeulen

Replacements: Fourie, Kitshoff, Nyakane, Snyman, Wiese, Hendrikse, de Klerk, Kriel

Romania XV: Simionescu, Manumua, Tomane, Gontineac, Onutu, Vaovasa, Rupanu; Hartig, Cojocaru, Gordas, Motoc, Iftimiciuc, Gorin, Neculau, Chirica

Replacements: Irimescu, Savin, Cretu, Iancu, Stratila, Boboc, Conache, Pop

Referee: Mathieu Raynal (France)