It was billed as “The Adventure Begins” on the front of the match programme and, if the evidence from Fratton Park last night is to be believed, it could be an epic journey that lasts long into next year.

Portsmouth experienced European competition for the first time and, after a slow opening against Vitoria Guimaraes, showed a distinct liking for it.

Those of a nervous disposition, though, should perhaps decline to purchase any travel tickets. It promises to be a bumpy ride, not one for the faint hearted. The first leg of their Uefa Cup first-round tie produced numerous chances, two missed penalties and a late rally from the Portuguese side.

Harry Redknapp, though pleased with the victory, gave warning of the dangers that lie ahead, especially in the return leg north of Oporto on October 2. “The tie is nowhere near over,” the Portsmouth manager said. “Sure, if we had got a third goal, that would have killed it off. But we know how dangerous they will be out there.”

Portsmouth’s reward for winning the FA Cup last season was a first trip into Europe in the club’s 110-year history. The draw could have been kinder, Guimaraes having finished third in the Portuguese league - above Benfica - during the 2007-08 campaign and having lost only 2-1 on aggregate to FC Basel in the Champions League third qualifying round.

The kick-off could have been kinder, too, with Redknapp preferring an 8pm start that would help create an intimidating atmosphere in the old stadium. Instead, the television paymasters got their way - as usual - and the game got underway in the daylight at 6pm. The home fans tried to whip themselves into a frenzy but with only intermittent success.

Not that, early on, they had much to enthuse about. Portsmouth probed intelligently, with Lassana Diarra gliding through the midfield and Jermain Defoe a persistent threat up front, but the end product was poor. Defoe, in particular, just could not find his range.

It did, though, take a fine save from Nilson, the Guimaraes goalkeeper, to paw away a fierce shot from the England striker. As Portsmouth, at last, upped the pace, John Utaka struck the foot of a post and Nilson, again, saved from Defoe. At the other end, David James, the England goalkeeper, enjoyed a quiet evening, his catch from a Desmarets effort no more than regulation.

Shortly before half time, the previously patchy encounter exploded into life. Diarra cut in from the left flank, exchanged passes with Defoe and clipped a shot past Nilson for his first goal since February. The lead might have lasted only three minutes but, after Sol Campbell had been judged to have bundled over Roberto, Fajardo thundered his penalty on to the crossbar and over. Again, James had little to do.

Spot-kick failure, it would appear, was infectious. Three minutes into the second half and as dusk fell, Defoe tumbled under the clumsy challenge of Moreno and Knut Kircher, the German referee, awarded another penalty. Another penalty, similar result, with Defoe’s tame attempt allowing Nilson the easiest of saves.

Portsmouth almost paid dearly, when Roberto scampered through on to a quickly taken free kick but drove wide. However, after Peter Crouch had headed straight at Nilson from Nadir Belhadj’s cross, the Algerian provided another perfect centre for Defoe to volley in from close range his fith goal in three games. “Jermain’s so sharp, he’s in great form,” Redknapp said.

In contrast, Manuel Cajuda, the Guimaraes coach, was crestfallen. “We were concerned about their big player [Crouch],” he said. “But it was the two smallest players [Diarra and Defoe] who scored.” His masterplan had failed miserably.

Portsmouth survived several scares as the “Pompey Chimes” rang out at Fratton Park. The match, if not the tie, was over and Portsmouth’s first European adventure had begun in encouraging fashion. Hold on tight; it may be some ride.

Portsmouth (4-4-2): D James — G Johnson, S Campbell, S Distin, N Belhadj — J Utaka (sub: P Bouba Diop, 74min), S Davis, L Diarra, A Traoré (sub: H Hreidarsson, 90) — J Defoe, P Crouch (sub: Kanu, 90). Substitutes not used: J Ashdown, Y Kaboul, A Mvuemba, G Little. Booked: Campbell.

Guimarães (4-5-1): Nilson — Danilo, Moreno, Gregory, J Momha (sub: L Silva Alves, 55) — Andrézinho, Fajardo (sub: Jean Coral, 64), João Alves, Wenio, Y Desmarets — Roberto. Substitutes not used: Nuno Santos, H Sereno, Carlitos, Tiago, Diogo. Booked: Roberto, Fajarda, Moreno.

Referee: K Kircher (Germany).