Australia captain Michael Clarke has apologised for being "out of line" in a spat with Dale Steyn in the tense finish to the series-ending Test against South Africa in Cape Town.

Until Ryan Harris' two late wickets gave Australia a 285-run victory at Newlands, with only four-and-a-half overs remaining, it appeared the outcome of the match would be heavily influenced by the controversial overturning of the dismissal of Vernon Philander, who top-scored with 51 not out.

Philander was adjudged caught at short-leg off Mitch Johnson only for video umpire Richard Illingworth to void on-field umpire Aleem Dar's decision, seemingly because he considered Philander's glove was off the bat when the ball brushed it.

Immediately after the decision, which occurred with about 15 overs remaining, Clarke was involved in a argument with non-striker Steyn that triggered the intervention of umpires Dar and Kumar Dharmasena.

Clarke himself had already been the subject of a lecture from the umpires, who were unhappy with how regularly the Australians were letting the ball hit the pitch when throwing the ball in, a tactic which generally aids reverse swing.

The Australia captain refused to give his opinion on the overrule. Customarily decisions are only change if the video umpire considers there is conclusive proof the initial decision was wrong. While Philander's thumb was off the bat it was uncertain the rest of his glove was also not touching the handle at the time it was grazed by the ball from Mitch Johnson, on the way to being caught at short-leg.

"If I'm not careful with what I say here, I'll get in trouble," Clarke said.

"We've played a fantastic Test match, we've beat the number-one team in the world in their own backyard. I think we've entertained the people that have watched, at the ground and back at home. South Africa deserve a lot of credit for the way they played throughout this series and the way they were led by Graeme Smith. I don't think it would be right for me to whinge or complain about that decision.

"I will always have my feelings about that decision, but over five days [it is minor because] I think we've seen some fantastic Test cricket in this Test and also across the series, and I think we really should be talking about that, rather than one decision."

The Australia captain did, however, concede he had been at fault in the showdown with Steyn that immediately followed the wicket of Philander being overturned.

"If anybody was out of line it was me and I apologise to the opposition player [Steyn] I was out of line to, a player who I have the utmost respect for, who tries to kill me every time bat, who batted exceptionally well, and I was out of line. If any player on either team it was me who was out of line," Clarke said.

"Let's just say he got me at a bad time. We just had a decision that didn't go our way that I would have liked to have seen go our way, but that's the game. Something was said to one of my teammates - I seem to make this mistake a few times - but I jumped in after him. It doesn't matter what happened. What I said was something out of character and I apologise for that. I shouldn't have said what I said."

Clarke also defended the conduct of himself, and his team, before and after the umpires complained about how the Australians were handling the ball in the field.

"The umpires were up me about a few things - that was one of them," Clarke said.

"I always believed that if you're in the ring you should be throwing the ball on the full because it's a 20-metre throw. If the guys are on the boundary you can accept that some guys can't throw it that far.

"Whatever criticism we cop for that I'm more than happy to cop, but I think our players understand there is a line and we know not to overstep that.

"We were asked by the umpires to make sure we were throwing the ball on the full and I think we accepted that and listened to that."

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