The Olympic silver-medallists Spain overcame a sluggish start to defeat a fighting South Africa 4-2 in the opening match of the men's hockey World Cup.
The South Africans, ranked 13th in the world, stunned the number three Spaniards with the first goal in the 16th minute through a lightning strike by Julian Hykes.
Spain, who lost to Germany in the Beijing Olympics final, hit back with two goals in three minutes through Roc Oliva and David Alegre to take a 2-1 lead by the 21st minute.
The African champions, however, equalised five minutes before the break when Ian Haley pushed in a goal following a rebound off a penalty corner.
Spain returned after the interval to score through Rodrigo Garza, before Pau Quemada made it 4-2 with a stinging penalty corner hit.
Spain and South Africa are drawn in group B alongside favourites Australia, England, India and Pakistan.
Group A comprises defending champions Germany, the Netherlands, Argentina, Canada, South Korea and New Zealand.
The 12-nation tournament began amid heavy security at the Dhyan Chand National Stadium in the Indian capital, with some 19,000 security personnel and 200 commandos on guard inside and outside the venue.