You wouldn't have given a quid for Connacht's chances after the first quarter, and scarcely tuppence by the interval. However, amid no little excitement, an extra ordinary turnaround at the Sportsground saw Connacht buck the trend of the Guinness Interprovincials with the series' first home win and so throw the championship wide open. Not what Ulster needed, but definitely what Connacht, the IRFU, the Irish team management, the sponsors and the interpros needed.

Still, in the euphoria of Connacht's win, it was still worth noting that Ulster are best placed after the opening salvos. By not contesting a late Connacht lineout on their line, and instead holding up Connacht's fifth closerange line-out-cum-maul of the match, Ulster not only deprived Connacht of a bonus point for a fourth try but earned one themselves for keeping the losing margin to within seven points.

"You never know, that could be crucial in a couple of months' time," mused Ulster hooker Allen Clarke, having been aware of that line-out's connotations at the time. Ulster thus hold a slender lead at the top of the table, but just as significantly are the only side with a couple of away games under their belt.

With three games to come at Ravenhill, they are still the best placed of a fairly evenly matched quartet. "I suppose we would have settled for that at the outset," said David Humphreys, consoling himself after a defeat that left a bitter taste for Ulster. Some of them were in tears afterwards, according to coach Harry Williams, underlining that these interpros mean more than they've ever done to the players at any rate.

The consequences of a defeat hammer home the importance of this win for Connacht. Their goose would have been well and truly cooked had they been left propping up the table, eight points off Ulster with two home defeats behind them. Hence, no less than Leinster the night before, their need was the greater and it showed. However, they got there in altogether different way.

It required a degree of brains, a subtle tactical alteration by Glenn Ross and plenty of physique, but the part of the anatomy that got them over the winning line more than anything else was nearer the heart.

"It was a gutsy effort," said Ross. "We've still lots to work on. We showed an improvement in the line-out, which was what we wanted.

"But again, we were naive in the first 20 minutes and we've got to get on top of that."

Indeed, it only required one turnover from the kick-off, when the Connacht pack picked and went once too often, for Ulster to retain possession without a break until Jan Cunningham's fourth-minute try.

Practically error-free and devoid of handling errors, their hammering away around the fringes, willingness to keep the ball moving in the tackle, continuity, support play and variety of options saw them again scale heights beyond Connacht, or indeed Munster or Leinster, so far. "We're trying to play enterprising rugby," said Williams, consoling himself after his first interpro defeat in 14 games as an Ulster coach. If nothing else, they're good to watch.

The omnipresent Andy Ward showed immense strength in muscling over for Ulster's second try of the match and his third in two games, and the damage might have been greater too - Simon Mason missed two penalties and a conversion.

Connacht couldn't get anywhere with their close-in, pick and drive game. Ulster, flirting constantly with the offside law, applied unrelenting fringe and midfield pressure defence. When a rare Connacht drive ended with Stephen McKinty's intercept and break-out, a Connacht supporter observed: "This is demoralising."

There was a fleeting glimpse of the midfield strength which would ultimately steer Connacht to victory when Diarmuid Reddan worked a novel Connacht move - and skipped Eric Elwood - off a scrum for Mervyn Murphy to make the vital incision and Pat Duignan to score with a pacy run on to his shoulder, a juggle of the ball and a spin out of Mason's tackle.

Even then Elwood's restarts were unusually awry, which was unfortunate as that was one of Connacht's few ways into the game, and Mason tacked on two more penalties to leave the visitors comfortably placed at the break.

Cue to Ross. Where before his obliterated back-row were submarining at scrums, thereafter they helped apply eight-man shoves and it showed. Debutant Ian Dillon came into that backrow as a second open side, and Connacht began attacking further out, Nigel Carolan getting a run outside Andy Park almost from the resumption before the covering Mark McCall and Humphreys sandwiched Alan Reddan into touch. But the game had changed.

Connacht still weren't clicking too impressively, handling errors and turnovers undoing the spadework of an outstanding Jimmy Screene and company. But, borrowing a leaf from Jack Charlton's manual - "put dem unda presha" - they kept pushing into Ulster's faces, tackled everything that moved, twisted and shunted the visitors' scrum and gradually Ulster cracked under the strain.

Unable to manufacture scores for themselves, Connacht eventually forced Ulster to cough up two charge-down tries - the brilliant Duigan blocked down Mason's clearance and then Shane McEntee charged down Humphreys' in-goal touch kick after a crucial shove and tweak on the Ulster put-in for Murphy to win a manic touchdown and emerge with a smile which would have lit up Eyre Square.

The ever-improving Murphy needs to add some more football to his repertoire but may well partner Duignan in a different shade of green one day.

"I thought Pat Duignan was magnificent," enthused Ross. "He made a try-saving tackle under the posts and in the same movement was across to the corner flag to make another (forcing Stanley McDowell to spill the ball over the line)."

Aside from his defence and brace of tries, Duignan was a live-wire midfield threat - once quick-wittedly taking the ball off Elwood's outstretched hand as Elwood dummied to kick ahead and then sliced through the gap.

The Canadian-born, Australian-reared son of Connacht parents - his mother represented the province at golf - last season never quite fulfilled the promise of a good start. But he's again off to a flyer, and with Kevin Maggs perhaps not making the best career move for his international prospects by switching to Bath, and poor Jonathan Bell seemingly terminally hamstrung, Duignan is becoming more and more of a contender for the Irish number 13 shirt.

Scoring sequence: 4 mins Cunningham try, Mason con 0-7; 16 Ward try 0-12; 32 Duignan try, Elwood con 7-12; 35 Mason pen 7-15; 38 Mason pen 7-18; 53 Duignan try, Elwood con 14-18; 70 Murphy try, Elwood con 21-18.

Connacht: W Ruane; N Carolan, P Duig nan, M Murphy, A Reddan; E Elwood (capt), D Reddan; J Screene, B Mulcahy, M Cahill, J Cullen, J Duffy, J Casserley, B Gavin, S McEn tee. Replacements: I Dillon for Casserley (halftime).

Ulster: S Mason; J Cunningham, S McDowell, M McCall (capt), A Park; D Humphreys, S Bell; J Fitzpatrick, A Clarke, G Leslie, M Rea, G Longwell, S McKinty, T McWhirter, A Ward.

Referee: G Black (Leinster).