England v South Africa, 1st Investec Test, The Oval, 3rd day July 21, 2012

Historic ton the fruit of Smith labours

Graeme Smith is due to leave England before the second Test to attend the birth of his first child but, as he marked his 100th Test with a century, his wife, the Irish singer Morgan Deane, joked on Twitter that her waters had broken already.

Smith, who will return in time to lead South Africa again at Headingley on August 2, laughed it off and said he tries not to read all her posts these days. "She's very impulsive, I'm trying to calm her down a bit," he said. "She's been very supportive though, considering she is going to give birth so soon."

If there was doubt about Smith's abilities as a batsman and leader, they have surely all been squashed. His 25th Test hundred was also his seventh against England, fifth in England and made him the seventh player to have scored a century on a landmark 100th Test.

Having also brought up big scores on both South Africa's previous tours here, combined with the fact that the team have never lost a Test when Smith has crossed the three-figure mark, his reputation is at its peak. The actual magnitude of what he has achieved hasn't formed a solid memory quite yet but he is starting to grasp what significance it has.

"It hasn't really sunk in yet. It was kind of surreal at the time. A lot of thoughts and emotions went through my head," Smith said. "It was a dream come true to come out and have the chance to do that. At one stage when Graeme Swann was spinning it past my bat, the hundred looked a long time away but once I fought through those tough times, it became a reality."

Smith said he expected a tough passage of play up front but knew that if he could see it through, there may be an opportunity to wrest control of the match. "It was a battle of attrition out there really," he said. "There weren't many scoring opportunities available to me so it was about being strong in my game plan. We expected that tactic from England this morning, that they would try and squeeze us as much as possible and cause us to make a mistake. We felt that if we could hold the game in that period of time we would be able to get a release somewhere."

After a cautious start, in which "the key factor was the way I left the ball this morning", Smith and Hashim Amla took 72 runs off the 13 overs before lunch, which included Smith's century. "When I got to 100, there was so many emotions: from the battle with Swann to knowing my wife is giving birth in three days' time," he said. "All those things were coming through. I don't even think I realised how I was celebrating. It is a blank moment in my mind."

There is still work to do before he turns his mind to fatherhood. "The way we bounced back with the ball has been probably the biggest achievement of this Test match so far," he said. "On day one, we were 50-50, we were solid without having an X-factor in our game. It's so easy to let the game drift from that position and be playing the rest of the Test match under massive pressure but we were able to keep England under pressure."

Now, Smith wants to go for the kill. He has already considered South Africa's strategy for closing out this match but was careful not to reveal too much. "I don't want to get too far ahead of ourselves. We've got two guys, Amla and Jacques Kallis, close to milestones tomorrow and I would love them to get there," he said. "It's been a difficult wicket to push on and score greater than three runs an over but if we set up a good base, hopefully we can do that."

Although Smith expects a tighter effort from England, he was bullish in his assessment of whether South Africa has what it takes to win. "We need to respect our opponent, they have the ability to bounce back," he said. "But we want to have a chance to push for a victory. I believe we have the ability to win, if we set the game up right. If we give ourselves the chance to bowl out England, I believe we've got the armoury to do that."

David Saker, England's bowling coach, called the pitch "subcontinental" and expects it to deteriorate, which could set the stage for the legspinner Imran Tahir to ignite his South Africa career. Smith was hopeful that would be the case. "It is quite dusty and quite dry. There is a turn available and it will be a good opportunity for Imran to get in," he said. "His form looks pretty solid. I don't want to put too much pressure on him but, on day five, if we are bowling for the win, he will have to play a prominent role."

Firdose Moonda is ESPNcricinfo's South Africa correspondent