The British and Irish Lions face an anxious wait over the fitness of Tomos Williams after the scrum-half suffered a hamstring injury in their commanding 54-7 win over Western Force in Perth on Saturday.
The Lions started their nine-game Australia tour in ominous fashion in front of 46,656 fans at Optus Stadium, with Williams and Elliot Daly bagging braces.
But Williams, a veteran of 65 tests with Wales, clutched at his left hamstring early in the second half after he acrobatically dived over the corner.
He limped off the field and did not return.
"It's too early to have an exact kind of diagnosis on that," Lions head coach Andy Farrell told reporters after the game.
"There were plenty of cramps last week (against Argentina). Let's hope it's one of those.
"I'm sure there's a little bit of concern there, but you can only deal in the here and now, so fingers crossed."
If Williams misses significant time, then the Lions might be tempted to seek emergency cover in the scrum-half position, where they have limited depth.
Scotland scrum-half Ben White was deemed unlucky to miss out on the Lions' 38-man squad.
He is currently in New Zealand as part of Scotland's tour squad for a trio of games in the South Pacific.
"We need to talk about that and assess that," Farrell said about a possible White call-up.
In a boost for the Lions, Ireland scrum-half Jamison Gibson-Park is expected to be available against Reds in Brisbane on Wednesday after missing the Force game with a glute injury.
"Jamison's fit to go, been training fully the best part of the week," Farrell said.
DYNAMIC POLLOCK
While they had some discipline problems early against a dogged Force, the Lions were ignited by the dynamic 20-year-old Henry Pollock.
Having made his debut last week in the Lions' shock defeat to Argentina in Dublin, Pollock enjoyed his first international start and superbly set up Williams in the 15th minute.
He was in the midst of the action after being in a fracas following a try to Daly and then sent to the sin bin after an accumulation of Lions infringements.
"He is certainly a point of difference. He is learning all the time," Farrell said of Pollock.
After overrunning a flagging Force, the weakest of the Australian Super Rugby franchises, the Lions are set for a sterner test against the Reds.
"They are good at playing the tight game, but can play expansive rugby as well," Farrell said of the Reds, who made the quarter-finals of Super Rugby.
"Will be a real tough test for us."