Kelechi Iheanacho seals FA Cup progress, but can he carry Leicester in Jamie Vardy's absence?

Iheanacho fires Leicester into FA Cup 5th round (1:04)

Kelechi Iheanacho's early strike propels Leicester City past Brentford. Watch the FA Cup on ESPN+. (1:04)

LONDON -- There was a time when arguments raged -- admittedly informed by the side of Manchester you favoured -- about who was the better young striker coming through the ranks: Marcus Rashford or Kelechi Iheanacho.

It was not quite as silly as it sounds now. Iheanacho scored 14 goals in his first season at Manchester City and was nominated for the FIFA Golden Boy award; Rashford got eight after coming from nowhere halfway through that 2015-16 campaign and while his potential was clear, the spectre of previous great United hopes -- hello, Federico Macheda -- hung over him.

Their careers have taken different paths ever since. Whereas Iheanacho gradually faded from relevance at City before moving to Leicester in 2017 and hardly kicking on from there, Rashford is one of the few genuine bright stars at Old Trafford for a club otherwise overwhelmed by ennui and expensive mediocrity.

Four years later, though, they have converged again, as potentially key men in deciding who qualifies for the Champions League. Rashford's long-term absence with a back injury might scupper United's chances, but Iheanacho's presence could be decisive for Leicester if he can maintain the form he has shown recently.

When the 23-year-old was taken off after 68 minutes of Leicester's FA Cup fourth-round tie against Brentford on Saturday, having scored what turned out to be the only goal in a 1-0 win, it was not because manager Brendan Rodgers was displeased. Rather, the last week has seen Iheanacho become one of the most important players at the club, who have tougher tests ahead.

Like Tuesday night and the Carabao Cup semifinal second leg against Aston Villa, which will be a tougher evening than it probably should have been for Leicester, who missed a terrific opportunity to put their Midlands rivals out of sight when drawing 1-1 in the opening game. Iheanacho will probably be required at Villa Park, with a start likely if Jamie Vardy's glute injury keeps him out.

Iheanacho has had to be patient. People often talk about the difficulty of being "another" centre-forward at Tottenham, feeding off scraps presented by Harry Kane's occasional absences, but it is not much easier at the King Power Stadium with Vardy around. Now, though, the absence of Leicester's talisman has increased Iheanacho's importance.

Having scored just 10 goals in his first two seasons at the club, Saturday's winner was his seventh of this season in all competitions, which is decent for back-up and exceptional for someone with only seven starts.

Being a permanent deputy is frustrating. Achieving any sort of momentum in your game is virtually impossible with 20 minutes here and a one-off start there, while there is also the knowledge that, no matter how well you play or how many goals you score, the main man will be in the team when he is ready.

"As a striker, you always want to get a goal and I'm not playing too much, so you have to keep your mentality up there, you need to keep going," Iheanacho said recently. "Whenever you get a chance, you take it. I just need to keep my head up, keeping working hard every day, so if I get my chance, I'll take it."

The improvement has been superb for a player who had seemed to lose his way, ineffective on the occasions when he did deputise for Vardy and suffering, like most Leicester players, from a post-Premier League title drift at the club before Brendan Rodgers arrived almost a year ago.

"Kel's getting better and better," Rodgers said after the Brentford match. "He's so efficient now in his game, working so hard, creates goals, scores goals. I'm delighted for him."

Vardy just turned 33, Leicester are still in three competitions and the pace of English football isn't getting any slower, so the safety net means Rodgers need not take reckless risks with his No. 1 forward. Because for all his progress, Iheanacho will not be a first choice any time soon.

His hold-up play can be ineffective, he does not press as relentlessly as Vardy and his finishing is not as decisive. However, if the worst you can say about Iheanacho is that he is not at the same level as one of the Premier League's best strikers in the last five years, it is hardly a grievous insult.

"They know that I trust them and they never let us down," Rodgers said about his second-string players. Far from disappointing, Iheanacho is among the best backup options in the division. In the modern game, that is extremely valuable.