Perfectionist Rafael Nadal went through his routine with military precision on the eve of a French Open final battle with an opponent who learned all about being well drilled during a national service stint.

Dominic Thiem bemoaned his four weeks of military service in 2014 as a "pain in the a**e" when asked whether it stood him in good stead to play at the highest level.

Thiem will be out of his comfort zone again when he goes into battle with Nadal in his maiden grand slam decider on Sunday.

The Austrian will be braced to come under fire from heavy artillery from the legendary Spaniard, who warned there is more to come after brushing aside Juan Martin del Potro in ruthless fashion on Friday.

Well drilled as ever, Nadal looked relaxed as he a huge crowd swarmed to Court 4 to see him practice on a glorious Saturday afternoon in Paris.

The world number one held serious discussions with coach Carlos Moya in an intense session in the heat as he studiously went about his business.

Just watching him have a hit is a sight to behold, the 32-year-old leaving no stone unturned as he goes in search of an incredible 11th title at Roland Garros.

Serving with venom and unleashing ferocious groundstrokes, Nadal treated his session on the cramped outside court like a final.

Ten times he has lifted La Coupe des Mousquetaires and the 'King of Clay' has looked as hungry as ever to retain his crown during yet another dominant run to an unprecedented 11th title in the French capital. 

Time and time again opponents have failed to find a formula to beat the top seed, who strides onto Court Philippe Chatrier like he owns it.

Thiem knows what it takes to defeat the 16-time grand slam champion, the Austrian being the only player to beat him on his favourite surface this year and also defeating him in Rome last year.

The seventh seed lost to Nadal at the semi-final stage in the French capital, however, and will be in uncharted territory when he plays the defending champion.

Thiem must show no fear when he steps into the firing line or he could be put to the sword by a global icon whose powerful weaponry has established him as one of the all-time greats.