The British and Irish Lions' game against a high-quality South Africa A side on Wednesday will be "pivotal" in determining Test selection, says former tourist Ugo Monye.

The Lions begin their three-Test series against South Africa on 24 July.

But Monye says Wednesday's supposed warm-up fixture in Cape Town is now "all but a Test match".

"Whatever team Warren Gatland had in his mind all gets trumped by how well some of these guys play against a fully loaded South African team," he said on BBC Radio 5 Live's Rugby Union Weekly.

"There is so much to be taken by what we will see and some players can play their way into the Test team.

"This is going to be the pivotal game. We always knew it was going to be big but there is talk of a fourth Test match and we are getting it."

'The tour starts on Wednesday'

Lions captain Conor Murray himself said the game was "almost a fourth Test" after it was announced he would lead the side for the first time.

The scrum-half starts alongside fly-half Dan Biggar and the pair will be tested against World Cup winner Faf de Klerk and Morne Steyn, who won the second Test and the series with the last kick of the game when the Lions toured South Africa in 2009.

Louis Rees-Zammit will also be eager to prove himself on the right wing, with Wales team-mate Josh Adams already eight tries to the good on the left and both will hope not to be outshone by Springbok star Cheslin Kolbe.

The back row is another area in which Gatland is spoilt for choice and Josh Navidi, Tom Curry and Taulupe Faletau will be dealing with the likes of 2019 world player of the year Pieter-Steph du Toit.

The Lions have so far claimed straightforward wins against Japan and provincial sides Sigma Lions and Sharks, but Monye says the step up in opposition "will expose exactly where" the side is.

"You expect them to score 70 points against a provincial side without any of their international players," continued Monye, who toured South Africa with the Lions in 2009.

"This is the first Test and the tour starts on Wednesday, quite simply.

"I just wonder how Warren Gatland plays it, because Wednesday will be so important to win psychologically, but how much of your hand do you show? It will be fascinating."

Players recognise they have an important chance to claim a Test jersey and hooker Ken Owens said he was looking forward to "a step up in intensity".

"For us players it is another opportunity to show what we can do to put a marker down for a place in the Test 23," he continued.

'Patched-up' South Africa team likely for first Test

South Africa head coach Jacques Nienaber's decision to field such a strong team was likely influenced by the impact of coronavirus.

The Springboks camp has recorded more than 20 cases so far and the entire squad recently spent six days isolating in their hotel rooms, making training impossible.

South Africa played their first Test since becoming world champions against Georgia on 2 July but had to cancel a repeat fixture because of Covid-19 cases.

That prompted director of rugby Rassie Erasmus to suggest the Lions change their schedule to include another game against South Africa A this weekend, but Gatland firmly rejected that offer.

Springboks captain Siya Kolisi is one of those to have tested positive for Covid-19 and, while the Lions may find out on Wednesday morning if skipper Alun Wyn Jones can make a miracle return from injury, South Africa face an anxious wait on their leader.

"Guys like Siya Kolisi, I doubt they are going to be ready for that first Test," said South African journalist Brenden Nel.

"They tested positive 14 or 15 days before the first Test. They have 10 days in isolation, then they have got to go through medical tests and even if they do they are not going to train a lot.

"That first Test you are going to see a very much patched-up team."

Line-ups

British and Irish Lions: Watson; Rees-Zammit, Harris, Aki, Adams; Biggar, Murray (capt); Jones, Owens, Sinckler, Itoje, Henderson, Navidi, Curry, Faletau.

Replacements: Cowan-Dickie, Vunipola, Fagerson, Beard, Beirne, Simmonds, Davies, Daly.

South Africa A: Le Roux; Kolbe, Am (capt), De Allende, Nkosi; Steyn, De Klerk; Kitshoff, Dweba, Nyakane, Etzebeth, Mostert, Van Staden, Du Toit, Wiese.

Replacements (to be cut to eight players before kick-off): Marx, Oosthuizen, Koch, Janse van Rensburg, Elstadt, H Jantjies, Kriel, Willemse, Smith, E Jantjies.