England star Courtney Lawes had back spasms before mauling Bulls

Courtney Lawes defied a back spasm to lead Northampton into their first Investec Champions Cup semi-final since 2011.

Saints swamped a Bulls team depleted by the absence of their South Africa stars 59-22 at Franklin’s Gardens with England scrum-half Alex Mitchell scoring two of their nine tries.

Northampton skipper Lawes also crossed and did so through gritted teeth having received treatment for an injury that placed his participation in the quarter-final in doubt.

“I had a back spasm at about one o’clock and that was fun! I am looking forward to playing game without wondering if I can run or not!” Lawes said.

“I’m just getting old. I have been dealing with a couple of issues the last few weeks and it is not ideal, but I could not pull out. I was ‘as long as I can run, I am playing’. I got a bunch of pain killers in me and cracked on.

“Knowing you can rely on your team-mates and the boys around you makes you just want to get out there and play with them. There was no way I was pulling out of this game.”

The Bulls were criticised for fielding a weakened team with their head coach Jake White insisting that it was because of injuries and the complications caused by travelling from Pretoria that influenced his team selection.

They trailed just 28-22 at half-time, but Northampton regained composure to run riot a week after dispatching Munster.

Saints director of rugby Phil Dowson insisted he did not take the quart-finals opponents lightly despite the accusation they were disrespecting European competition by leaving out the likes of World Cup winners Willie le Roux, Canan Moodie and Kurt-Lee Arendse.

“I’ve seen the quality and strength in depth of rugby in Pretoria and how big it is, it’s unbelievable in that region,” Dowson said.

“And they have produced some of the best players in the world in the last 20 or 30 years.

“So we’re aware of the production line of very good players they have, so we knew not to take them lightly.

“The South Africa teams have added in terms of quality of players they have and their heritage.”

White denied he had prioritised the United Rugby Championship over Europe by fielding his second team.

“We want to be in this competition. I’m not whinging about being here, I’m loving this competition,” he said.

“It’s so close to Test rugby. The styles varies a little bit, maybe there’s more attack, but the intensity and fight to win is there.”