Hull coach Lee Radford was relieved to watch his side make a winning start to his reign, in the knowledge that they are sure to improve as the Super League season goes on.
Radford's men clung on for a 36-34 victory over Catalan Dragons at the KC Stadium after the Frenchmen's last-gasp rally fell just short.
The Dragons, who had trailed 36-22 going into the last five minutes, would have earned a point had Thomas Bosc been able to convert Zeb Tai's last-minute try but he was off target for the fourth time in the match.
After outscoring their visitors by eight tries to seven, Hull deserved their opening-round victory but Radford knows they will need to considerably tighten their defence when they go to St Helens next Friday.
"It was really important we got off to a good start and we're happy to take the two points," said Radford, who succeeded Australian Peter Gentle in the close season.
"For whatever reason, we capitulated in the last 20 but it gives us something to work on on Monday, that's for sure.
"Our right edge is certainly going to get some traffic next Friday night."
Long-serving centre Kirk Yeaman scored two tries, climbing to fifth in the club's all-time list on 157, but it was Australian Jordan Rankin, one of six new signings on display, who stole the show.
The former Gold Coast Titans player scored a 70-metre solo try and creating two others in a crucial seven-minute spell in the second half that turned the game Hull's way.
"I thought all our new boys did a really good job," Radford added. "And they will all get better.
"We will get a bit more cohesive. We'll certainly get that defensive issue sorted out."
The Catalans were on course for their first win at the KC Stadium since 2008 after dominating the first half to lead 16-12 but coach Laurent Frayssinous was alarmed at the way his side collapsed after the break.
Left winger Damien Cardace's hat-trick of tries was in vain and Frayssinous is facing an anxious wait to discover if forward Olivier Elima is to face punishment after being put on report for an ugly tackle on Hull hooker Aaron Heremaia.