England launched their home World Cup with a laboured 35-11 bonus-point victory over Fiji at Twickenham that exposed numerous areas of concern for head coach Stuart Lancaster.
A strong opening quarter saw the hosts establish a 15-0 lead through a penalty try and touch down from the excellent Mike Brown, setting the scene for a comfortable win in a ferociously competitive Pool A that also includes Wales and Australia.
But instead of issuing a statement of intent in their quest for the Webb Ellis Cup, they allowed Fiji to force their way back into contention and lost direction until the arrival of their bench in the final 20 minutes generated fresh momentum.
Lancaster said: "It was a big occasion and there were a few nerves. We got a good lead but didn't put the nail in the coffin.
"We had to work hard and that last try late in the game was a massive relief. I don't think we were ever going to be on the end of a hiding at 18-11 but it was nervy. We didn't get our game plan into action. We have to be more direct, we were a little bit lateral.
"Our bench made us much quicker. But overall it was a big game to play and if you'd have offered me a four-try bonus I'd have taken it."
England captain Chris Robshaw said: "The bonus point might be hugely important. The opening game can be edgy and you have to give a lot of credit to Fiji, we knew it was going to be tough."
After a glittering opening ceremony involving Prince Harry and England's 2003 World Cup hero Jonny Wilkinson among others, Lancaster's men, wearing their red kit, entered the last quarter only 18-11 ahead but their opponents were tiring and late persistence resulted in a second try from man of the match Brown before Billy Vunipola secured the bonus point at the death.
Lancaster will declare objective achieved in securing a vital five-point haul, but the recurring problems of error-count, breakdown, scrum and discipline must be urgently addressed ahead of next Saturday's pivotal showdown with Wales.
Fiji were heroic in defence and rose to the occasion magnificently, with giant wing Nemani Nadolo scoring a popular first-half try, and on this evidence they are capable of causing an upset of their heavyweight rivals in the group. England were first off the mark when George Ford slotted a penalty after Fiji's scrum crumbled in front of the posts.
The lead was stretched to 10 points in a damaging period for the Islanders that saw them scatter before a line-out drive and as the Red Rose pack neared the whitewash, they desperately entered from the side.
England crashed over but referee Jeco Peyper chose to award a penalty try and sent scrum-half Nikola Matawalu to the sin-bin in the process with Ford converting. Fiji gifted the hosts a second try by opting for a throw to the back of the line-out when only five yards from their line.
The ball was athletically picked off by Tom Wood and rapidly threaded wide, with intelligent play from Jonathan Joseph creating an overlap that was finished by Brown. Matawalu sought instant redemption for his indiscipline with an electric break from a scrum that saw him side-step Jonny May, and he was only denied a try following a last-gasp intervention by Brown.
Fiji won the ensuing five-metre scrum against the head, however, and when Ben Volavola spiralled a kick into the left corner Nadolo outjumped Anthony Watson to touch down.
Ford and Nadolo exchanged penalties to give England an 18-8 interval lead, but Fiji occupied the driving seat. The third quarter drifted along, producing few highlights, and Twickenham was growing restless, with a penalty conceded at the scrum against the head causing more anxiety.
Nadolo missed two penalties but then barraged his way through and when England infringed again, Volavola was handed back the kicking duties and responded with three points.
The arrival of the home bench had the desired impact and Fiji had clearly given their all, and after the red shirts pummelled away Brown showed trademark tenacity to power over.
Vunipola followed him over in injury time, with Owen Farrell converting both tries.
England: Tries: Penalty, Brown 2, B. Vunipola.
Cons: Ford, Farrell 2. Pens: Ford 2, Farrell.
England: Brown, Watson, Joseph, Barritt, May, Ford, B. Youngs, Marler, T. Youngs, Cole, Parling, Lawes, Wood, Robshaw, Morgan.
Replacements: Burgess for Barritt (62), Farrell for Ford (62), Wigglesworth for B. Youngs (52), B. Vunipola for Marler (52),
Webber for T. Youngs (74), Brookes for Cole (68), Launchbury for Parling (52).
Not Used: M. Vunipola.
Fiji: Tries: Nadolo. Pens: Nadolo, Volavola.
Fiji: Talebula, Nayacalevu, Goneva, Lovobalavu, Nadolo, Volavola, Matawalu, Ma'afu, Koto Vuli, Saulo, Ratuniyarawa,
Nakarawa, Waqaniburotu, Qera, Matadigo.
Replacements: Ravai for Ma'afu (74),
Tuapati for Koto Vuli (75), Colati for Saulo (77), Cavubati for Ratuniyarawa (41), Yato for Waqaniburotu (60).
Not Used: Kenatale, Matavesi, Tikoirotuma.
Sin Bin: Matawalu (13).
Referee: Jaco Peyper (South Africa).