England needed an own goal by Paraguay captain Carlos Gamarra to grind out a 1-0 victory in Saturday's Group B opener.
England made a dream start on a hot afternoon at the Waldstadion when Gamarra headed a David Beckham free kick into his own net after four minutes.
But they failed to show the killer instinct coach Sven-Goran Eriksson had urged and at times rode their luck against skilful opponents.
England, who had lost two and drawn one of the opening games in their last three tournaments, will be satisfied though with a winning start in a physical encounter.
OWN GOAL
The first attack produced a goal when Beckham's ball soared into the danger zone and Gamarra sent a glancing header past keeper Justo Villar under pressure from Michael Owen and John Terry.
Things got worse for Paraguay four minutes later when an injured Villar was replaced by 20-year-old reserve Aldo Bobadilla, the fastest keeper substitution in World Cup history.
The newcomer promptly gave away a free kick inside his area, Frank Lampard's shot came back off the wall and though he ballooned the follow-up, the midfielder then warmed Bobadilla's gloves with a 25-metre drive.
England were in control, despite several crunching tackles by both sides, with Paraguay defending tenaciously and shooting from distance.
Striker Nelson Valdez had their best chance before the break with a shot that flew narrowly wide.
Paraguay were more ambitious after the break and Valdez again made the more threatening moves.
Striker Owen, recently back from a lengthy injury layoff, made way after 56 minutes for midfielder Stewart Downing.
Joe Cole, who had been giving Paraguay a torrid time down the left, was pushed up as a strike partner for Peter Crouch, himself standing in for injured Wayne Rooney.
Paraguay nearly levelled when Paul Robinson flapped at a cross but Carlos Paredes failed to get his effort on target.