Was last night proof that Guardiola values Premier League success over European glory?

Manchester City Football Club are really good. The football they played last season was a thing of beauty, the fact that they cantered towards the Premier League title by mid-April and achieved a record-breaking 100 points, thanks to a late strike from Gabriel Jesus on the season's final day away at Southampton, is something that will never be forgotten. It will, quite literally, go down in history.

This time around things have followed a similar pattern at the Etihad, despite a slight wobble around Christmas time which saw the Sky Blues fall to two surprise defeats within the space of a week against Crystal Palace and Leicester. Pep Guardiola's side have epitomised the word dominant, destroying almost everything in their path as they look to blow a hole in the history books by winning the quadruple.

Having already claimed the League Cup for the second time in as many seasons in February, should they once again lift the Premier League title next month, beat Watford in the FA Cup final and win the Champions League at the start of June, they will become the first side in footballing history to ever win four major trophies in a single season. There's an extremely good chance that they will do this, too.

Currently in pole position to win the Premier League for the second consecutive season, trailing challengers Liverpool by just two points with a game in hand over their Merseyside rivals, the Cityzens are also just a game away from winning the FA Cup thanks to a slender 1-0 win over Brighton on Saturday evening.

City have won the Premier League three times in the previous decade. They've won the League Cup four times in the previous decade. They've won the FA Cup, too, in 2010-11, but as fantastic as all these achievements are, as precious as they are to the club, one thing is still missing - dominance in the Champions League. Last season they were dumped out by Liverpool in the quarter-final phase, that would've hurt. This time around they're at risk of being humbled by another English side, this time Mauricio Pochettino's Tottenham Hotspur.

Last night saw a massively out-of-sorts City side fall to narrow defeat against Spurs in their brand new sparkling arena, with Son Heung-min scoring the decider twelve minutes from time after Harry Kane had limped off with what looked to be a season-ending ankle injury. So what happened to City last night? They were a shadow of their normal selves in north London, looked bereft of confidence and lacked their usually so poignant cutting edge in front of goal.

Star performers went missing, while Pep Guardiola's refusal to change things until in was too late left everyone watching on astonished. Was last night merely part of the Spaniards bigger plan, or did he in fact just make an incredibly rare error and get it all wrong at the Tottenham Hotspur Stadium?

Much question surrounded Sergio Aguero prior to last nights match, after the Argentinian front man picked up a knock in City's 2-0 win over Fulham last week. Pep opted to played the Premier League's current leading goalscorer, but it wasn't the right decision. A dubious penalty awarded to the visitors inside the first 15 minutes, after Spurs full-back Danny Rose was adjudged to have handled the ball in the area following another farcical review from VAR, gave City the perfect opportunity to grab a foothold in the game.

Sergio stepped up, trademark relaxed stance, Slim Shady-esque bleached blonde hair perfectly intact, patiently waiting for the referee's whistle. Surely this is 1-0, it has to be. Sergio doesn't miss penalties, not this season anyway. But he's not fit, he's not sharp, he looks a little burnt out, truth be told. A poorly taken spot kick, aimed slightly towards the left hand side of Tottenham's recently-calamitous Hugo Lloris, with barely any conviction or passion, sees the French shot stopper effortlessly palm the ball away before Tottenham are able to get it clear and retreat. Close call, but you'd argue that justice was served as the decision to award a penalty in the first instance seemed extremely harsh.

Normally, something like a missed penalty would spur a team like City on to up their game and rectify their previous mistake. They'd have known that Lloris' save would have given Tottenham a boost last night, and should have been ruthless to ensure they didn't allow them a route into the game with it poised so evenly at 0-0. We've seen this time and again from the world's best sides, including City. But last night things went the other way; extremely rare sloppiness started to creep into their game, the usually-so-reliable David Silva wasn't finding openings, Sterling couldn't get past Tripper for love nor money, Mahrez cut in on his left foot so many times that it started to become comical.

City were frustrated last night; they looked fed up, almost offended by the rigorous game plan executed to perfection by Tottenham. The visitors were restless; they're usually so calm and collected, so silky and smooth, like George Clooney in any movie ever. But last night they were more like a hapless actor who'd forgotten his most important line when it mattered most. It's not surprising, though, after all this is a team so elite that they still find themselves vying for every possible trophy even at this late stage of the campaign.

The downside to constant success is the fact that fixtures are relentless, there's no rest. Players cannot afford to let their performance levels drop, but of course they will because they're not robots. City's squad has depth and quality, but key players must remain in the starting line-up each week so that they have the best possible chance of winning, even if they're not fully fit. Aguero is a perfect example, he should have been rested last night, with backup striker Gabriel Jesus rewarded for scoring the match winner in Saturday's FA Cup semi-final against Brighton with a start against Spurs. Instead, the burnt out South American was chosen to lead the line and ultimately, it cost City.

With questions surrounding Guardiola's choice of personnel last night - leaving out potential player of the season Bernardo Silva while starting bit-part player Riyad Mahrez on the right, risking a semi-fit Aguero up front and swapping Kevin De Bruyne for Ilkay Gundogan in the middle of the park, the fact that Pep waited until the game had practically finished before introducing two of his most influential players - De Bruyne and Leroy Sane - was all just a bit baffling, wasn't it?

Squad rotation is key at this stage of the season, and with the vast amount of quality City have available to them, it's not a shock that different members of the squad will be introduced to ensure the team remains energised. What is extremely confusing it why Guardiola didn't change things earlier on, when it was clear to everyone that things were not going for his side. De Bruyne and Sane spent the majority of the second half parading themselves along the touchline, going through the motions - stretching hamstrings, quadriceps, calves, ankles and groins in some of that magnificent bench wear City are donning this term, but to no avail.

After Sterling's 19th unsuccessful take on, Mahrez's 80th shit cross, Gundogan's 120th sideways pass, we're all left thinking "surely Pep makes a change soon". It never comes, though, why? Because it seemed as though a 0-0 draw or 1-0 defeat is more than manageable, easily rectifiable in the second leg on home turf next week. It was like Pep was scared to risk Sane and De Bruyne ahead of Sunday's crunch league fixture against Palace, what other answer is there for it? He had two proven world class match winners on his bench but didn't use them until right at the very end, it was so unbelievably strange.

It's no secret how highly Guardiola thinks of title rivals Liverpool. After years in Spain winning La Liga with Barcelona and dominating proceedings in Germany with Bayern, despite the odd inconvenience from Madrid and Dortmund, his teams have always remained fairly unchallenged.

This isn't the case in England, however. The truth is, Liverpool scare Guardiola. Jurgen Klopp scares him, too, because he is the one manager who rivals him as the best coach in world football, in charge of a side who rival City as the best in England and possibly the world right now. Liverpool are firmly in Pep's head at the moment, and though they too find themselves still in the Champions League, the competition the Reds are ever so desperate to win is the Premier League, and Guardiola will do anything to prevent that from happening.

Back-to-back title wins in the Premier League haven't happened since the days of Sir Alex Ferguson at Manchester United, but City are on course to do it this season, barring any late slip-ups. Despite the Sky Blues never winning the UCL, replicating United's success ten years ago seems more important for a club who have never really clicked with the Champions League, which is fair enough. Of course, winning them both is the dream for City, but if one has to be sacrificed in order to benefit the other, after last night it looks clear where Pep's priorities lie.