After the appointment of head coach, Tjaart van der Walt at Monnas, Garsfontein appointed assistant coach, Johan du Plessis as the new head coach. Duppie must be one of the last "full-time" coaches at any top rugby school who is not employed full time at the school itself.
His career as rugby coach kicked off in 1995 at Laerskool Louis Leipoldt. He coached primary schools rugby up until 2000 and won the league 5 out of the 6 times during that period.
He got involved in high school rugby in 2001 where he started coaching at Hoërskool Centurion at u/14 level. They won the Stadsbeker in that year. He went on to coach the u/15s in 2002, u/16s in 2003 and was then appointed in 2004 and 2005 as 1st team coach. In 2005 Centurion’s 1st team won the Pretoria Stadsbeker for the first time.
In 2006 he decided to move on to senior club level and was appointed as the Carlton League 2nd team coach at Naka Bulls. In 2007 and 2008 he coached the Carlton 1st team at Naka Bulls. "Coaching at senior club level I learnt a lot in terms of people skills and working with senior players and I thoroughly enjoyed it but due to work pressure and the hours required as head coach of a Carlton Club I decided to move back to coaching at school level".
He got involved at Hoërskool Garsfontein in 2009 and upon his request was appointed the coach of the u/14A team. He remained coach of the u/14s up until 2011. During that time he was intimately involved in the turnaround of Garsfontein’s rugby and the strategy behind it. In 2012 and 2013 he was appointed as u/16A coach at Garsies.
By this time Garsies started to turn the ship and in 2013 the u/16A team won the Blue Bulls Macro Schools league for the first time in the school’s history and that side also beat some big names during the year like Paarl Gimnasium, Outeniqua Michaelhouse etc.
The 2013 U/16A side was also the first A-side in Garsfontein’s history to win Waterkloof who at that stage was a powerhouse in Pretoria and in the country. In 2014 to 2016 he was appointed with Tjaart van der Walt as Garsfontein’s 1st team coaches. These were indeed the most successful years in Garsfontein’s short history so far. A number of firsts occurred:
- In 2014, 2015 and 2016 Garsfontein won the Blue Bulls Macro Schools title. The school’s 1st team never won those titles before. They also beat Waterkloof for the first time in history in 2014.
- In the same years, they played in three consecutive Beeld Trophy Finals and won the Beeld Trophy for the first time in the school’s history in 2015 and again in 2016.
Garsfontein’s 1st team has been under the top 20 teams in the country in from 2013 onwards, but the 2014 1st team was widely regarded as one of the top 5 teams in that year.
His highly successful career is reflected in some interesting statistics that Duppie provided. He coached in 476 games over the last 22 years of which his sides has been on the winning side in 397 games, a win percentage of 83.4%. "My proudest moment as coach were the two Beeld Trophy wins of 2015 and 2016 and the game which will always stand out in my memory, which was possibly the greatest comeback in Beeld Trophy history, was our win against Monnas in 2015 in the Beeld Trophy Semi Final."