Brace yourselves for a roaring climax in Cardiff. This victory means the Republic of Ireland will travel to Wales knowing that, if either side wins Monday’s feverishly anticipated Celtic duel, it will be certain of finishing in second place, at least, in Group D. Top spot will be up for grabs in the unlikely event of the leaders, Serbia, stumbling at home to Georgia. “It’s there for us,” said Martin O’Neill. “Let’s go for it.”

Daryl Murphy made sure there was no spoilsport deviation from that script by scoring twice here to dispatch the group’s bottom side. Murphy and Callum O’Dowda, in particular, made strong cases for roles in Monday’s match and eased criticism of O’Neill in advance of a much fiercer test.

Opinions among Irish supporters are evenly split as to whether O’Neill and his assistant, Roy Keane, have got the best out of the resources available to them so there was widespread bemusement when the Football Association of Ireland let it be known that the pair have been offered a new contract even before the outcome of the current campaign is clear.

O’Neill intimated that one of the reasons he is eager to remain at the helm is to integrate exciting young players. He began that process against Moldova by giving a first competitive start to 22-year-old O’Dowda. The Bristol City winger was chosen ahead of Aiden McGeady to replace the suspended James McClean, who will probably return to the showdown in Cardiff, as will Robbie Brady.

O’Dowda’s selection was quickly vindicated here. So was the manager’s decision to start Murphy up front in spite of calls for him to hand first international starts to the Preston striker Sean Maguire or Aston Villa’s Scott Hogan.

Murphy began alongside Shane Long and the 34-year-old took his Nottingham Forest form on to the international stage, hitting two goals in the first half, doubling the tally he had managed in his previous 29 games for his country.

It took only 90 seconds for Murphy to strike. Ireland’s first goal involved no conjuring from Wes Hoolahan, another encouraging inclusion in the starting line-up. Instead Stephen Ward created it with a long throw-in, which was flicked on inadvertently by a defender. Murphy reacted quickest to hook a left-footed volley into the net from five yards.

The thrusting O’Dowda tried to increase their lead after 10 minutes, curling a shot just wide from the edge of the area, and he continued to justify his inclusion by producing a lovely flourish in the 15th minute that should have resulted in another goal. He showed power and subtlety to elude two defenders before calmly teeing up Long, who shot wide from 12 yards.

Then Ward and Murphy combined again, yielding a more elegant goal than the first. Ward raced on to a fine diagonal pass from Hoolahan before delivering a grand cross to the back post, inviting Murphy to boom a header back across the goalkeeper and into the bottom corner.

O’Dowda might have inflicted more damage moments later but was thwarted by Ilie Cebanu. Then Ireland’s goalkeeper, Darren Randolph, had to demonstrate his alertness to prevent Moldova from scoring out of the blue, Sergiu Platica’s sudden blast from 25 yards bringing a fingertip save from the Middlesbrough player.

Chris Coleman will have noted that not everything was rosy for Ireland in the second half. The hosts let the initiative slip as the visitors passed the ball better, albeit without threatening a breakthrough.

And the form of Long remains a worry. The Southampton striker has not scored for club or country since February and looked forlorn in front of goal here. He made an easy chance seem unfeasibly awkward in the 66th minute when, after a break by Hoolahan and O’Dowda, he skewed the ball wide from six yards as the goalkeeper lay helpless.

O’Neill craved a goal for Long almost as much as the player did himself and he left him on until the 82nd minute before introducing Maguire, whose arrival drew a huge cheer from the home crowd. O’Neill knows Long’s woes leave him with another big selection decision to make for the Wales match. “He remarked to me going in [at the end of the game] that he can’t buy a goal at the moment and that might sum it up,” said O’Neill.

“He had some great chances that normally he would have taken. Sometimes your confidence is affected by that. But it is what it is.” Asked whether Murphy had cemented a starting place, O’Neill replied: “Who knows?”

That, at least, was a less enigmatic response than the one offered by the Moldovan manager, Igor Dobrovolski, when asked whether Alexandru Gatcan deserved the red card he was shown for thrusting his head into that of Harry Arter in the closing minutes “He didn’t headbutt him, it just happened,” reasoned Dobrovolski.

Monday’s contest will be feisty, too, although O’Neill said he hoped it would not be unduly influenced by memories of the Neil Taylor tackle that left Séamus Coleman with a broken leg when the countries drew in Dublin in March.