The six times capped scrum-half was in the original squad for the championship and was named on the bench for the opening day clash in Paris, where Ireland kicked off their campaign with a dramatic late victory thanks to Johnny Sexton's extra-time drop goal.

McGrath didn't get on the park, with Conor Murray's experience deemed vital in the white-hot pressure of the final 10 minutes in Stade de France, and he was then left out of the squad to face Italy in round two, with Kieran Marmion given the nod.

McGrath returned to Leinster to maintain his fitness, but injured his knee against Scarlets and has not played since.

He expects to be back just in time for Leinster's Champions Cup quarter-final against Saracens on April 1, but has been forced to watch on from the sidelines as the national team make history.

“It's tough, definitely, especially having been part of the first two weeks,” McGrath said. “They've done well since then against Wales and Scotland but the competitor in you...you get a bit jealous being on the outside, but I wish them all the best and look forward to watching them win this weekend.”

McGrath has taken to calling the Ireland team 'them' rather than 'us' since returning to the province to rehab his knee injury and admits he doesn't quite feel part of the history that's been made.

“I was definitely feeling good about my game even though I obviously didn't get on against France, myself and Joey [Carbery] were left on the bench – it was tough to bring a 9 and 10 into that atmosphere, but it was brilliant watching those 41 phases.

“I wasn't selected against Italy but I got the chance to come back and prove myself for Leinster.

“I'm not part of it since, so obviously the injury came at such a bad time.

“I was involved in the first matchday, I was in camp, in training, in myself I know I am part of that squad... it's just difficult when you're not in there a few weeks... I hope they get on and win it all now.”

The 25-year-old has returned to straight-line running as his rehab progresses and is hopeful he can take the next step in time for the visit of the English giants in just over two weeks' time.

“The past two weeks I've just been strengthening up the quads and calf muscles, getting massages and the likes,” he said. “The straight-line running felt pretty food, changing direction now will test it but I'm confident it'll go well.”