Giants, who won 22-16, lost full-back Olly Ashall-Bott in the early exchanges and Leeds’s Ash Handley, who was Super League’s top try scorer last season, hobbled off, also in the first half.
Ian Watson, in charge of Giants in match action for the first time, said Ashall-Bott was “a little bit sore” after the game.
“He has had a few injuries in the past,” said Watson.
“We will assess him over the next two games.”
Handley, meanwhile, suffered suspected medial ligament damage to a knee.
Leeds coach Richard Agar said: “We will get him scanned, but I would say he will be a risk for round one.
“He is sore at the moment and we have our fingers crossed it is a low-grade medial strain, but even a low-grade medial strain would put him in tremendous doubt at this stage, I reckon.”
Despite those setbacks, both coaches were pleased with their side’s performance, in a physical contest. Watson said: “James Gavet was outstanding, James Greenwood, Josh Jones and Olly Wilson as well.
“I thought our middles were really good, but there’s always things to work on.
“We wanted to have a really good mentality at the start and get into an arm wrestle and we did that.
“Everything else on the back of that, we will learn from.”
Leeds were without any of their established half-backs or first-choice centres, but Agar was “really pleased with a lot of aspects of what we did”.
Rhinos rallied after trailing 22-4 on 53 minutes and Agar reflected: “I thought for long periods we did some really good stuff.
“Of course, there were some areas we need to work on.
“Pre-season trials always give you that, but we’ve come out of it – with the preparation we had for this game – with a stack of positives and very much knowing what we’ve got to work on over the next couple of weeks.”
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